US.F.G. Newsletter Vol. 8 No. I April, 1997

Officers and Appointed Staff 1998-2000

President .... Ralph Mathewson 914-994-3992 Secretary .... Eva Mathewson

3551 NE Surf Dr., Lincoln City OR 97367 ewillis@lewiston.com

Vice President Charles L. Moon . 707-822-6063 155 Myrtle Court, Arcata CA 95521-6511 clmoon@sprintmail.com

Treasurer .... Don Dunn . . . . . . 937-426-5112 993 Renown Rd., Dayton OH, 45430-1112 ddunndtn@aol.com

Membership .. Jean Marr ...... 919-595-3870 P.O. Box 1815, Kernersville NC 27285 mystixls@nr.inti.net

Editor ....... Robert Strickland 512-892-1887 6408 Earlyway Dr., Austin TX 79749-1632 rstrick@compuserve.com

SEND US YOUR E-MAIL ADDRESS

Since communication in the USFG is very difficult, due to our wide-spread membership, if you are a USFG member and have e-mail capability, would you please send your e-mail address to our Vice President, Charles Moon, clmoon@sprintmail.com? A complete membership list will make necessary

communications much more viable! Moon will compile the addresses and distribute the list to the Mathewsons, Don Dun, Jean Marr and Robert Strickland.

NOTICE: The opinions expressed in the newsletter are those of the editor, contributing members, or quoted authors, and do not neces­sarily represent the United States Faceters

Guild or its membership. This newsletter is for the express purpose of sharing information

with the members and other faceting Guilds, and has no intent to show preference to, or cause damage to any product manufacturer or commercial company.

Correspondence concerning the content of the newsletter should be sent to the Editor (see officers, above). Exchange bulletins and newsletters should also be sent to the Editor.

IN THIS ISSUE

USFGNews ........................... 3 Membership Application Form . . . . . . . . . . . 4 The Plan View Shape ................... 5

Fred Van Sant OMNI and Breakpoint Methods . . . . . . . . . . 6

Fred Van Sant Sunrise Cut ........................... 7

Fred Van Sant OMNI Standard Oval Brilliants . . . . . . . . . . . 8

Robert W. Strickland Old Uncuttable Revisited . . . . . . . . . . . . . . . . . . 19

Robert H. Long

OMNI Egg and Shield ................. 21 Robert W. Strickland

The USFG N ewletter is a quarterly publication of Tips for Gemstone Microphotography 23 the United States F aceters Guild. It is delivered by first class mail to all paid members of the Guild at the end of March, June, September, and December. The 1997 volume number is 7. Membership dues are $15 per year and are payable to the USFG treasurer.

Scott and Susan Wilson What is a Tier? ....................... 27

Fred Van Sant Preforming and Pavilion Rough Shape . . . . 28

Fred Van Sant Northwest Internatl. Faceting Conference . 29

Page2

US.F. G. Newsletter Vol 8. No. 1 April, 1998

Eledion Results

Outgoing Secretary, Charles Moon has tabulated the ballots, and they have been confirmed by Jean Marr. The results are:

President Vice President Secretary Treasurer Membership Editor

Editor Resigns

Ralph Mathewson Charles L. Moon Eva Mahewson Don Dunn Jean Marr Robert Strickland

First off, thank you for your vote of confidence by reelecting me as your Editor. I apologize for not publishing the December issue. It is with regret that I announce that I must resign as Editor. After numerous attempts to juggle my responsibilities to family, career, church, GemCad and this newsletter, I find I must give up something. Over the past three months, I have come to the conclusion that I cannot both edit this newsletter and upgrade GemCad. For every one comment I get about this newletter, I get asked about ten times, "When will GemCad for Windows be available?" I have made much progress on this front the past few months, but it has been at the expense of this newsletter. Again, please accept my apologies for failing to publish the December issue.

Dues Due?

Check your mailing address label for the date of your last issue. Please also check your name and address for accuracy. Dues are $15 per year. Make check payable to Don Dunn, USFG Treasurer (address on inside cover).

If you are not yet a member, please complete the application on the back of this page and send it to Don Dunn ( address on inside cover) with your $15 check.

Meetpoint Techniques

Many thanks to Fred Van Sant for contributing several articles. The first, entitled "The Plan View

· Shape" (page 5) gives a summary of several methods of meetpoint faceting that generate the girdle outline (the plan view) in different ways.

Next comes an article that compares and contrasts the OMNI method and the Breakpoint Method (page 6).

Both of these techniques were introduced last issue. In last issue can be found the "Alternate Pavilions for the Oval Checkers." These cuts are designed to generate the girdle outline using the technique Fred has termed the Breakpoint Method. I owe Fred an apology for publishing these designs without explaining the Break­point Method in more detail. Fred has come through again with an excellent article explaining the Break­point Method. After you read Fred's article, take another look at his Oval Checkers in the last issue. Fred's article goes on to compare and contrast the Breakpoint and OMNI Methods. Fred's "Sunrise'' (page 7) is a new Breakpoint design. Fred also contributed "What is a Tier" (page 27) and "Preforming and Pavil­ion Rough Shape" (page 28).

More on the OMNI Preforming Method

Next comes my article (page 8-13) showing step-by­step how to cut the pavilion to my OMNI Ovals (page 14-18) using the OMNI Method. The article goes on to compare the OMNI technique and the Breakpoint Method on the same design.

Bob Long has contributed a new version of his design, "Old Uncuttable." Bob's "Old Uncuttable Revis­ited," (pages 19-20) uses the OMNI preform instead of the CAM preform of the original. Unlike the other OMNI designs in this and last issues, in the "Old Uncuttable Revisited" the OMNI facets are temporary and are cut off by the other pavilion facets.

OMNI Shield and OMNI Egg

As promised in the previous issue, I have contributed OMNI versions of a shield and egg cut brilliant-style. Both show how the OMNI technique can create compli­cated outlines simply. Both designs have all OMNI facets cut at the same angle and mast-height!

Tips for Gemstone Microphotography

Scott and Susan Wilson have contributed an excel­lent article, page 23-27, on photographing your faceted gemstones, reprinted from the July-August 1997 issue of the New Mexico Facetor 's Guild Newsletter.

Northwest International Faceting Conference Rapidly Approaching! See pages 29 and following.

Page3

US.F G. Newsletter

UNITED STATES FACETERS GUILD

Application for Membership

The USFG is open to faceters everywhere. Our primary goal is to improve the art and science of faceting through our newsletter and correspondence. Our secondary goal is to improve competitions and competition rules, both in the U.S. and internationally. Officers are elected every two years for 2 year terms; l 99e begins with new officers. Issues are voted on by mail. Members receive our Quarterly Newsletter - usually about 20 pages each, and the right to participate in the USFG activities. New members receive a copy of our Constitution upon request.

Name Date

Street Address ---------------- Telephone _____ _

City, State, Zip ---------------------------

I am a faceter --- I am interested in becoming a faceter __ _

I compete or have competed at the following levels:

Junior Novice Intermediate Advanced

I do not wish to compete.

Master

I have a display case __ 12 stones __ 20+ stones __ Educational__ Other __

Which machine do you cut with?

Do you cut commercially? Dealer?

Do you need help with, or information about, your type of machine? __________ _

Have you judged in competitions? __ Interested in judging? ____________ _

Have you given talks or written articles on faceting?

Special talents or interests to share?

Enclosed is my check for $15 (U.S.) for 1 year membership in USFG _________ _

$16 (Canada), $19 (Overseas)

MAKECHECKSPAYABLETODONDUNN

MAil., TIIlS FORM PLUS CHECK TO: Don Dunn, 993 Renown Rd.

Rev. 6-96 Beavercreek, OH 45430 Telephone: (937) 426-5112

Page4

US.FG. Newsletter Vol 8. No. 1 April, 1998

The Plan View Shape A summary of stone shaping by Fred Van Sant

The purpose of this article is to bring attention to the variety of methods by which stones can be shaped. It is important that we know about these methods, and that they be named and de-

. scribed, for if they are not th�rn when we begin cutting a design we may not see the easiest and best ways of cutting it. If we don 1 t have the idea of a method we will not see it in the diagram. From personal experience I can assert that the designer himself may overlook the best cutting sequence.

If the design allows only one method, and that method will cause too much waste of material, you should look for another design. But you should not give up too easily; it often happens that the diagram sheet does not show all possible ways of preforming, or even the best way. If you like the design, study it closely for other methods before giving up on it.

The term 11Preforming" was originally used to apply to the rough elimination of material to obtain a shape approximating the finished stone shape. In faceting, the term has come to mean making a precise shape matching the one shown on a plan view on the diagram sheet. Since in some methods of cutting, the shape is not made until the pavilion is a lmost or completely f inished, the 11Pre" in "Preform" seems inappropriate. So for

· this article we a re concerned with methods of making the final shape of the stone.

In general, all shaping (or cutting) begins either (A) at the gird le with a set of 90 ° gird le facets, or ( 8) at a culet point made by a set of facets at a given angle. Both of these methods are based on two settings derived from the faceting machine--1) a constant angle, and 2) a constant dop arm position which results in equal Normal Intercepts for the facets cut. On vertical mast machines, equal Normal intercepts are obtained by keeping the mast in a fixed location and having a positive stop for the swing of the dop arm.

(A) GIRDLE PREFORMING: In this method the shape is made first and directly, using an angle of 90 degrees. Before computer design entered the scene, the rolled girdle, which imi­tated cut diamonds, was popular and showed up in many designs. With computed designs the faceted

· girdle made the design much easier to compute, made for an even-width girdle, and also for easier alignment after transfer-dopping the stone, so it

. has mostly replaced the rolled- girdle. Girdle Shaping begins with a set of ECED

facets at 90°. If cut on symmetrical index num­bers a circular shape results, but any index num­

. bers may be used.

Meet l ine Preforming: After making the primary set of ECED girdle facets, secondary girdle facets are cut to meet the lines made by the primary set. See article in USFG Newsletter, September 1993, called 11Circular Preforming 11

•

Other non-circular girdle shaping is done by a combination of ECED facets and measurement. Most common is measuring length and width to conform - the stone to the L/W of the design sheet. Also measuring girdle facet lengths can make the desired shape.

(8 ) POINT AT CULET: This starts with a set of (at least 3) facets cut at the same angle and positive stop to a point centered on the dop axis. The point made may be a Temporary Center Point (TCP) or a Permanant Center Point (PCP). There are several methods to be followed:

Cor ner .L.ocator Angle Method (C.L.A.M ). Two sets of culet facets a re cut to a TCP. These c reate lines which intersect one or both sides of corner gird le facets. Then gird le facets at 90° are cut to meet the comer lines. After the shape is made the culets are overcut and lost by faceting the permanent pavilion facets.

Sometimes designs have such lines con­necting the culet point to a comer, so the shape can be made in the same manner using facets that are permanent .

.Qenterpoint Angle Method (C .A.M.): Culet facets are cut at gi rdle indexing to a TCP, using· angles such that when the stone is 'rounded off at 90° using the same set of index numbers, the desired shape will result.

Omni: See next page. If all the outline points necessary to create the shape have, in the plan view, straight lines connecting them to the culet point, then the design can be preformed by the Omni Method.

Breakpoint: See next page. Breakpoint and Omni adapt well to many modern designs with steep barion break facets. R. Strickland1s Diamond Checker Oval in the Mar-June issue is an example.

Meet point: The outline shape develops as the result of cutting all the pavilion facets. Se­quencing varies with each design, but they all start from a Center Point. Sometimes considerable up­and-down mast adjustments are required. In General: All methods which start at the culet require the cutter to traverse the entire vertical dimension of the stone to ar rive at the table, so there is a greater number of facets through which small errors can accumulate than is the case where an accurate girdle is made first. Therefor, start­ing at the Center Point requires great accuracy on the pavilion meet points to make the outline as precise as possible. D

Page5

US.F. G. Newsletter Vol 8. No. 1 April, 1998

NEWER METHODS OF MAKING THE STONE'S SHAPE -- by Fred Van Sant Neither of these methods described below is totally new. Both have been done before, but neither was seen as a GENERALMETHOD which could apply to a variety of shapes until 1997. Both pertain to the pav ilion, which is to be cut first. Both are special sequences of Meetpoint cutting. CAM, Omni, and Breakpoint can be mixed on the same stone ..

THE OMNI METHOD

SEQUENCE: 1. A set or sets of facets are cut to a Permanent Center Point (PCP). 2. A set of 90° girdle facets is cut to make the size

. of the stone. This creates the primary gird le points for step three. 3. Remaining gird le facets are cut in a meetpoint sequence, starting from primary girdle points. The shape is now made, but the girdle is not level. FEATURES: • The step 2 girdle facets are cut to make points farthest from the stone center. • The culet point can be final. • There is a minimum of overcutting, lost mate­rial, lost time, or mast movement. • The primary girdle points wil l be at the final girdle elevation. The other girdle facet points will be closer to the culet. • The go0 girdle facets have different index num­bers than the culets; if they are the same it is a CAM preform. • The Omni can work on a variety of shapes. • On the plan view the lines from the culet connect with points on the outline. Later overcutting (break facets, for example) may obscure this feature, but it is essential to the Omni preform.

Omni and Breakpoint Compared These methods are not really new; what is

new is our thinking about them and giving them a name to keep them in mind when either designing or looking for the best way to cut an existing design. Certain types of designs lend themselves to Omni and Breakpoint cutting: Cushion Triangles, Cush­ion Squares and Rectangles, and Ovals can often be cut by one of these methods, even if an Omni or Breakpoint sequence is not given.

For both methods steps 1 and 2 are the same. Omni then chain-cuts the girdles; Breakpoint chain-cuts the break facets. Since most Omni designs will have break fac::;ets which make a level girdle, there is often little difference in the ap­pearance of the pavilion plan view.

If points between culet and break facets are floating, it cannot be cut Breakpoint, because in chaining the break facets, the points made are 4-facet points. Omni allows for such points to float.

THE BREAKPOINT METHOD

SEQUENCE: 1. A set or sets of facets are cut to a Permanent Center Point. (PCP) 2. A set of go0 girdle facets is cut to make the size of th� ?tone. _This creates the primary girdle points for step three. 3. All break facets are cut meetpoint, beginning at primary girdle points. 4. Remaining 90° girdles are cut meetpoint using break facet indexing to make a level girdle line. FEATURES: • The step 2 girdle facets are cut to make points farthest from the stone center. • The cul et point can be final. • There is a minimum of material loss, time loss, or mast movement. • On the plan view of an OMNI Preform the lines from the culet meet points on the outline. The Breakpoint Method is free from this restriction, but the girdles must be cut on the same index numbers as the break facets if a level girdle is to be made. • Breakpoint will work on a variety of shapes. • The Breakpoint method does make the plan view shape, but because the shape comes at the end of the sequence, it is not considered a preform method.

If in the plan view a design has lines from the culet which meet, or could if extended meet, points on the outline, then it is possible that the stone can be preformed by the Omni method, oth­erwise it cannot.

If the intermediate points are 4-facet points, and the culet lines could meet points on the outline, then it might be cut either Omni OR Breakpoint.

With Omni, step 3 makes the shape; with Breakpoint, step 4 makes the shape.

If all the points on the outline can be made by cutting girdle facets which meet lines from the culet, then the design can be preformed by Omni. Lines which bend passing through the break facets indicate the pavilion may be cut Breakpoint but not Omni; however, if such bending lines are not needed to make the shape, it may still be cut Omni. For an Omni shape, it is essential only to have sufficient culet-to-girdle lines to make the shape.

Page6

US.FG. Newsletter Vol 8. No. I

Sunrise 96 Index Gear Angles for RI == 1.7+

Crown: 1. 4 at 45.01 °

2. 4 at 39.47°

3. 4 at 46.04 °

4. 2 at 42.75°

5. 4 at 37.00°

6. 4 at 31.29°

7. 4 at 22.31 °

8. 4 at 26.43°

9. 4 at 23.44°

L/W = 1.239306 Table Area = 31,T TfW. =- .54 C/\N = .1634 PfW = t,5387 H/W = . . 7221

A/W = .2987 B/W = .4659 F/VV = .1305

VF = .3146 GVF = .00453

Indices 2,46,50,94. 6,42,54,90. 10,38,58,86. 2 4, 72. 7,4 1,55,89. 15,33,63,81. 3,4 5,51 ,93. 10,38,58,86. 18,30,66,78.

%

Pavilion Instructions 1. Cut set 1 to a PCP. 2. Cut sets 2,3,4,5 to meet the PCP. 3. Cut 2 at 90° at 24 and 72 to set length. 4. Cut break facets 6,7,8 to meet as shown. 5. Cut girdle facets at 90° starting at

corner to make level girdle line, using facets 6, 7,8 indices.

Pavi l ion: Indices 1. 4 at 40.90° 17,3 1,65,79. 2. 4 at 41.00° 10,38,58,86. 3. 4 at 41.00° 6,42,54,90. 4. 4 at 41.00° 2,46,50,94. 5. 2 at 41.00° 2 4,72. 6. 4 at 70.00° 10,3 8,58,86. 7. 4 at 70.00° 6,42,54,90. 8. 4 at 10.00° 2,46,50,94.

Desinged by Fred W. Van Sant

Page 7

April, 1998

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U.S.F G. Newsletter Vol 8. No. 1 April, 1998

OMNI Standard Oval Brilliants

by Robert W. Strickland

Several shapes lend themselves to easy cutting with the OMNI Method, described in the last issue. Cushions such as the cushion triangle, square, and pentagon in the last issue are ideally suited to the technique. Ovals are also good candidates. Commercial settings for oval stones are available in numerous sizes. The different sizes have different length-to-width ratios. The most common are 1 .2 : 1, 1 .25: 1 , 1 .33: 1 , 1 .4 : 1 , and 1 .5: 1 . Some sizes fall in between, but most standard sizes are within a few percent of these ratios. I have designed a series of ovals in these aspect ratios that take advantage of the OMNI Method. See pages 14-18 for the diagrams. These are the easiest oval brilliants to cut that I know of. The designs are found on pages

Other uses for these ovals are in cutting a replace­ment stone for a setting or cutting to maximize yield for a piece of rough.

All of these OMNI Ovals have the same cutting sequence. The fattest two ( 1.2: 1 and 1 .25: 1 ) are cut using an 80 index gear. The remaining are cut on the more common 96 index.

As in the other OMNI designs in the previous issue they have the following advantages: 1 . All preform facets are kept ( and not cut off by

subsequent facets). 2. The girdle outline is established early in the cutting

sequence. If you look carefully at the diagrams you might note

that the break facets don't quite meet up. This can easily corrected during prepolish or even polish with a tiny change in angle. This problem is due to the unequally-spaced OMNI facets that meet at the tempo­rary center point. I could have included facets that cut off the OMNI facets to fix the meets, but it hardly seemed worth the confusion that that would introduce on the diagrams.

The designs are for Topaz RI. of 1 .63 or higher. The culet angles are below the critical angle for quartz. You

can adapt the designs to quartz by just omitting the little culet facets .

The companion article on pages 8- 13 shows the pavilion of one of these designs, the 1 :33 : 1 ratio, cut at each stage. For those of you that missed last issue, it might also serve as an introduction to the OMNI technique.

The article goes on to compare the OMNI Method to the Breakpoint Method. Showing the same design cut with the two methods really shows the difference between the two techniques.

Farewell Fine Facetors from Down Under

From the North York Guild in Canada comes the sad news that Peter Collins of Australia died of a massive heart attack last month. Peter was one of the driving engines behind the 1200 member Australian Faceting Guild during most of its history. He had been one of the founders of this organization, its President and as well the long-time editor of Facet-Talk, its newsletter. At the time of his death, he was working on a book about faceting co-authored by John Broadfoot.

Before his death, Peter Collins informed us by e-mail of the death of noted Australian faceter Frank Dickson. Frank died of a severe heart attack December 9. Frank was 81 . Peter wrote, "Several USFG members have stayed at Cremore, Sydney, with Frank and his wife Nola on visits Down Under, and he was held in very high regard. Frank was a member of several Interna­tional Challenge teams and was AFG faceting champion in 1988, the year he married Nola . . . He was one of our finest facetor-jewellers and won the jewellery section of our annual competition several times." Frank was the winner of the Australian International Faceting Competition in 1988. Frank's eight stones entered in their Guild's 1997 Warwick Competition lost no points for polishing ( 160 out of 160) and lost only 0.05 point for scratches (79.95 out of 80). Frank pioneered the use of Teflon-based "Super- Lube" lubricants.

Page 8

US.F G. Newsletter Vol 8. No. 1 April, 1998

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OMNI OVAL- - OMNI SEQUENCE

First we will cut the des ign with the OMNI Method as shown in the diagrams . The cutting sequence and appearance i s the same with al l of the OMNI Oval s . Choose the diagram that bes t matches the legth- to-width rat io of your rough . This article as sumes a 1 . 3 3 to 1 ratio . The diagram for 1 . 3 3 : 1 is given for a 9 6 gear .

The first step i s to cut four of the Step 1 facets to a point .

1 4 2 . 0 0 04 - 44 - 5 2 - 9 2

After thi s your stone will look l ike the top picture . These four facets meet at a temporary center point (TCP ) , and the remainder of the step 1 facets are cut at the same mast height and to this same TCP .

lB 4 2 . 0 0 1 1 - 17 - 3 1 - 3 7 -5 9 - 65 - 7 9 - 8 5

Next , we cut the step 2 facets to the same TCP . ( This will require a slight change in mast height . )

2 4 1 . 7 0 2 0 - 2 8 - 6 8 - 7 6

The stone will now look l ike the middle picture at the left .

Next we are ready to establ ish the length of the stone . I f we want to cut the largest pos sible stone from this design ( assuming that the rough is at least as fat as the 1 . 3 3 : 1 ratio , that i s , i f our rough L/W measures less than 1 . 3 3 ) then we meet the point indicated by the circle . We cut four girdle facets :

Gl 9 0 . 0 0 2 0 - 2 8 - 6 8 - 7 6

The stone will look l ike the bot ­tom picture . We wil l next cut step G2 to meet the indicated point .

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Vol 8. No. 1 April, 1998 S I DE

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After cutting G2

G2 9 0 . 0 0 13 - 3 5 - 6 1 - 8 3

to the meet point indicated on the previous page , the result is shown in the top picture at the left . Note that the temporary girdle is not level . This i s normal and is the main di stingui shing character­istic of the OMNI method . The meetpoint for next step G3 i s indicated . The meetpoint s for the remaining girdle facets chain around the stone .

G3 9 0 . 0 0 0 7 - 4 1 - 5 5 - 8 9

This results in the middle pic ­ture . Note that the fal se girdle l ine is gett ing deeper .

The girdle outl ine is completed with the step G4 facet s .

G4 9 0 . 0 0 0 2 - 4 6 - 5 0 - 94

1------96-�-----<,__-----------i At this point , we have etabl ished the final girdle outl ine of our stone ! All of the step 1 and step 2 facets are permanent facets . I f we were cuting a CAM preform, these would all be cut off later .

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The level of the f inal girdle l ine starts where step 2 meets step G2 . It i s a good idea at this point to measure the amount of material left for the crown . I f there is not enough to complete the crown , you might cons ider making a second pass around the girdle to make a smaller stone or prepare to shor­ten the crown by tangent - ratio scal ing .

Next , change to the prepol ish ( 12 0 0 to 3 0 0 0 ) lap and prepolish all facets . For all but the largest stones , the remainder of the pavil ion facets can be cut directly on the prepol i sh lap s ince they remove very l ittle material .

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The next step is t o cut the barion facets that serve to level the girdle . The meet point for step 3 is shown in the bottom pi cture of the previous page .

3 6 6 . 6 1 13 - 3 5 - 6 1 - 8 3

Step 4 is cut to cont inue to chain the level girdle around the stone . It will meet step the point indi ­cated in the top picture .

4 6 8 . 7 6 0 7 - 4 1 - 5 5 - 8 9

Step 5 finishes the level girdle . I t i s cut to the meet point indi ­cated in the middle picture .

5 7 0 . 0 0 02 - 4 6 - 5 0 - 94

I f cutt ing in quartz or beryl (RI < 1 . 6 ) stop here ! Steps 7 and 8 will be below the critical angle for quartz .

The cutt ing sequences for the other aspect rat ios are the same as for this des ign .

BREAKPOINT METHOD

Now we can compare the OMNI se­quence above to the same des ign cut us ing the Breakpoint Method . Al though this design is better suited to the OMNI Method , by cutt ing the same des ign us ing the Breakpoint Method , we can gain ins ight to the di f ferences between the methods .

The two sequences are exactly the same through the bottom of the first page where the girdle facets Gl establ ish the f inal size of the stone .

With the Breakpoint method , the barion facets are cut before the remaining girdles . These begin with step 3 and are cut to the same point indicated on the bottom picuture of the f irst page .

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April, 1998

After cutt ing step 3 ( Breakpoint Method )

3 6 6 . 6 1 13 - 3 5 - 6 1 - 8 3

your stone will look l ike the top picture .

The next set of barion facets chains to the indicated meet ­point .

4 6 8 . 7 6 0 7 - 4 1 - 5 5 - 8 9

The resul t is the middle picuture

The last barion facet chains to the indicated meetpoint .

5 7 0 . 0 0 0 2 - 4 6 - 5 0 - 94

The resul t is the bottom picture Next we cut the remaining girdle facets to level the girdle . The G2 barion facets meet the indi ­cated point .

Thi s is the distinguishing feature of the Breakpoint Method . The high- angle break ( or barion ) facets chain around the stone .

In this des ign note how the edges between the break facets l ine up with the edges between the culet facets . This is NOT typical of Breakpoint des igns . In general , with a Breakpoint des ign these edges will not l ine up . This gives the des igner more flexi ­bility but is usually of l ittle concern to the cutter .

Note that with the OMNI sequence , we would have the final girdle outl ine after having cut the same number of facets as we have so far with the Breakpoint Method . In general , the OMNI Method gives the finished girdle outl ine as soon as possible in the cutt ing sequence .

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After cutting step G2

G2 9 0 . 0 0 13 - 3 5 - 6 1 - 8 3

to the meetpoint shown at the bottom of the previous page , the level girdle start s to work its way around the stone as shown in the top picture . The next set of girdle facets

G3 9 0 . 0 0 0 7 - 4 1 - 5 5 - 8 9

is cut to the point indicated in the top picture . The resul t is the middle picture . See how the level girdle chains around the stone?

The f inal set of girdles

G4 9 0 . 0 0 0 2 - 4 6 - 5 0 - 94

completes the level girdle .

The result is exactly the same as with the OMNI Method . In this design , the OMNI sequence is preferable to the Breakpoint sequence since it generates the outl ine sooner and with fewer large changes in mas t height .

So are there any advantages to the Breakpoint Method as compared to the OMNI Method? The advantages are primarily to the des igner and not the cutter . For a design to be cut with the OMNI Method where the OMNI facets are preserved , the edges between the barion facets must precisely l ine up with the edges between the OMNI facets . ( The OMNI facets in the " Old Uncuttable Revis ited" are cut of f . )

1------96------1------------t Although these OMNI ovals are better suited to the OMNI than the Breakpoint Method , by comparing the same des ign cut with both methods , I hope you have a better understanding of the dif ferences between the two methods .

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OMNI Oval 1 . 2 0 : 1 ( OMOV1 2 0A . GEM) by Robert W . Strickland 3 / 1 3 / 9 8

Angles for R . I . = 1 . 63 6 9 facets + 1 6 facets on girdle = 8 5 2 - fold , mirror- image symmetry 8 0 index

April, 1998

r l

L/W = 1 . 2 0 0 T/W = 0 . 7 04 T/L = 0 . 5 8 7 P/W = 0 . 5 2 0 C/W = 0 . 12 9 H/W = ( P+ C ) /W+0 . 0 2 = 0 . 6 6 9 P /H = 0 . 7 7 7 C/H = 0 . 19 3 Vol . /WA

3 = 0 . 2 7 8

PAVILION 1 4 2 . 0 0 0 3 - 3 7 - 4 3 - 7 7 - TCP

0 8 - 14 - 2 6 - 3 2 - 4 8 - 54 - 6 6 - 72 2 4 2 . 1 0 1 7 - 2 3 - 5 7 - 6 3 TCP Gl 9 0 . 0 0 1 7 - 2 3 - 5 7 - 6 3 Establ i sh length G2 9 0 . 0 0 1 1 - 2 9 - 5 1 - 6 9 OMNI : Meet 1 - 2 -Gl* G3 9 0 . 0 0 0 6 - 3 4 - 4 6 - 74 OMNI : Meet 1 - 1 - G2 G4 9 0 . 0 0 0 2 - 3 8 - 4 2 - 7 8 OMNI : Meet 1 - 1 -G3 3 6 7 . 65 1 1 - 2 9 - 5 1 - 6 9 Level girdle 4 6 9 . 2 0 0 6 - 3 4 - 4 6 - 74 II

5 7 0 . 0 0 0 2 - 3 8 - 4 2 - 7 8 II

6 4 0 . 7 6 1 1 - 2 9 - 5 1 - 6 9 Meet 1 - 1 - 3 - 4 7 4 0 . 6 9 8 0 - 4 0 Meet culet 8 4 0 . 92 2 0 - 6 0 Meet culet

CROWN A 3 8 . 2 6 0 2 - 3 8 - 4 2 - 7 8 Leave s ome girdle B 3 8 . 8 2 0 6 - 3 4 - 4 6 - 74 Level girdle C 3 3 . 3 7 1 1 - 2 9 - 5 1 - 6 9 I I

D 3 3 . 6 2 1 7 - 2 3 - 5 7 - 6 3 I I

E 3 1 . 5 0 8 0 - 4 0 Meet A-A at girdle F 2 9 . 3 6 0 9 - 3 1 - 4 9 - 7 1 Meet B - C at girdle G 2 7 . 5 1 2 0 - 6 0 Meet D -D at girdle H 1 9 . 1 0 0 4 - 3 6 - 44 - 7 6 Meet A-B - E - F J 15 . 9 2 14 - 2 6 - 54 - 6 6 Meet C - D - F - G

0 . 0 0 Table

*OMNI preform is formed by s teps 1 -G4 . The girdle l ine will not be l evel until s teps 3 - 5 are cut .

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OMNI Oval 1 : 1 . 2 5 ( OMOV125A . GEM ) by Robert W . Strickland 3 / 13 / 9 8

Angles for R . I . = 1 . 63 6 9 facets + 1 6 facet s on girdle = 8 5 2 - fold , mirror- image symmetry 8 0 index

April, 1998

r l L/W = 1 . 2 5 3 T/W = 0 . 72 7 T/L = 0 . 5 8 0

P/W = 0 . 5 3 9 C/W = 0 . 134 H/W = ( P+C ) /W+ 0 . 0 2 = 0 . 6 9 3 P /H = 0 . 7 7 8 C / H = 0 . 19 3 Vol . /WA 3 = 0 . 3 04

PAVILION 1 4 2 . 0 0 0 3 - 3 7 - 4 3 - 7 7 - TCP

0 9 - 14 - 2 6 - 3 1 - 4 9 - 54 - 6 6 - 7 1 2 4 1 . 9 0 17 - 2 3 - 5 7 - 6 3 TCP Gl 9 0 . 0 0 17 - 2 3 - 5 7 - 6 3 Establ i sh length G2 9 0 . 0 0 1 1 - 2 9 - 5 1 - 6 9 OMNI : Meet 1 - 2 -Gl* G3 9 0 . 0 0 0 6 - 3 4 - 4 6 - 74 OMNI : Meet l - 2 -G2 G4 9 0 . 0 0 0 2 - 3 8 - 4 2 - 7 8 OMNI : Meet l - l -G3 3 6 7 . 1 6 1 1 - 2 9 - 5 1 - 6 9 Level girdle 4 6 9 . 05 0 6 - 3 4 - 4 6 - 74 II

5 7 0 . 0 0 0 2 - 3 8 - 4 2 - 7 8 II

6 4 1 . 05 12 - 2 8 - 5 2 - 6 8 Meet 1 - 1 - 3 - 4 7 4 0 . 6 9 8 0 - 4 0 Meet culet 8 4 0 . 74 2 0 - 6 0 Meet culet -

CROWN A 3 9 . 7 7 0 2 - 3 8 - 42 - 7 8 Leave some girdle B 3 9 . 2 7 0 6 - 3 4 - 4 6 - 74 Level girdle C 3 3 . 7 9 1 1 - 2 9 - 5 1 - 6 9 II

D 3 3 . 13 17 - 2 3 - 5 7 - 6 3 II

E 3 3 . 0 0 8 0 - 4 0 Meet A-A at girdle F 2 9 . 7 5 0 9 - 3 1 - 4 9 - 7 1 Meet B - C at girdle G 2 6 . 9 7 2 0 - 6 0 Meet D-D at girdle H 18 . 4 9 04 - 3 6 - 44 - 7 6 Meet A-B - E - F J 17 . 0 2 14 - 2 6 - 54 - 6 6 Meet C - D - F - G

0 . 0 0 Table

*OMNI pre form i s f ormed by steps 1 -G4 . The girdle l ine will not be level until s teps 3 - 5 are cut .

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OMNI Oval 1 . 3 3 : 1 ( OMOV13 3A . GEM ) by Robert W . Strickl and 3 / 1 3 / 9 8

Angles for R . I . = 1 . 6 3 6 9 facets + 1 6 facet s on girdle = 8 5 2 - fold , mirror- image symmet ry 9 6 index

April, 1998

r l L/W = 1 . 3 3 0 T/W = 0 . 7 9 2 T/L = 0 . 5 9 5

P/W = 0 . 5 6 5 C/W = 0 . 14 7 H/W = ( P+C ) /W+ 0 . 0 2 = 0 . 73 2 P/H = 0 . 7 7 2 C/H = 0 . 2 0 1 Vol . /WA 3 = 0 . 3 4 7

PAVILI ON 1 4 2 . 0 0 04 - 44 - 5 2 - 9 2 - TCP

l l - 1 7 - 3 1 - 3 7 - 5 9 - 6 5 - 7 9 - 8 5 2 4 1 . 7 0 2 0 - 2 8 - 6 8 - 7 6 TCP Gl 9 0 . 0 0 2 0 - 2 8 - 6 8 - 7 6 Establ i sh length G2 9 0 . 0 0 13 - 3 5 - 6 1 - 8 3 OMNI : meet 1 - 2 -Gl * G3 9 0 . 0 0 0 7 - 4 1 - 5 5 - 8 9 OMNI : Meet 1 - 1 -G2 G4 9 0 . 0 0 0 2 - 4 6 - 5 0 - 94 OMNI : Meet 1 - 1 -G3 3 6 6 . 6 1 1 3 - 3 5 - 6 1 - 8 3 Level girdle 4 6 8 . 7 6 0 7 - 4 1 - 5 5 - 8 9 II

5 7 0 . 0 0 0 2 - 4 6 - 5 0 - 94 II

6 4 1 . 0 2 1 4 - 3 4 - 6 2 - 8 2 Meet 1 - 1 - 3 - 4 7 4 0 . 4 5 9 6 - 4 8 Meet culet 8 4 0 . 3 5 2 4 - 7 2 Meet culet

CROWN A 4 1 . 8 8 0 2 - 4 6 - 5 0 - 94 Leave some girdle B 4 0 . 2 3 0 7 - 4 1 - 5 5 - 8 9 Level girdle C 3 6 . 4 9 1 3 - 3 5 - 6 1 - 8 3 II

D 3 4 . 9 0 2 0 - 2 8 - 6 8 - 7 6 II

E 3 6 . 0 0 9 6 - 4 8 Meet A-A at girdle F 3 1 . 5 7 1 0 - 3 8 - 5 8 - 8 6 Meet B - C at girdle G 2 8 . 6 7 2 4 - 72 Meet D - D at girdle H 2 0 . 3 3 0 5 - 4 3 - 5 3 - 9 1 Meet A- B - E - F J 16 . 6 7 1 6 - 3 2 - 64 - 8 0 Meet C - D - F - G

0 . 0 0 Table

*OMNI preform is f ormed by steps 1 - G4 . The girdle l ine wil l not be level unti l step s 3 - 5 are cut .

Page 16

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OMNI Oval 1 . 4 0 : 1 ( OMOV14 0A . GEM) by Robert W . S trickland 3 / 1 3 / 9 8

Angles for R . I . = 1 . 6 3 6 9 facet s + 16 facets on girdle = 8 5 2 - fold , mirror- image symmetry 9 6 index

April, 1998

f 1 L/W = 1 . 4 0 1 T/W = 0 . 844 T/L = 0 . 6 0 2

P/W = 0 . 5 8 6 C / W = 0 . 15 4 H/W = ( P+C ) /W+ 0 . 0 2 = 0 . 7 6 0 P/H = 0 . 7 7 2 C /H = 0 . 2 0 2 Vol . /WA

3 = 0 . 3 8 4

PAVILION 1 42 . 0 0 04 - 44 - 5 2 - 9 2 - TCP

12 - 17 - 3 1 - 3 6 - 6 0 - 6 5 - 7 9 - 84 -2 4 1 . 4 0 2 0 - 2 8 - 6 8 - 7 6 TCP Gl 9 0 . 0 0 2 0 - 2 8 - 6 8 - 7 6 Establ i sh l ength G2 9 0 . 0 0 13 - 3 5 - 6 1 - 8 3 OMNI : Meet 1 - 2 - Gl * G3 9 0 . 0 0 0 7 - 4 1 - 55 - 8 9 OMNI : Meet 1 - 1 -G2 G4 9 0 . 0 0 0 2 - 4 6 - 5 0 - 94 OMNI : Meet 1 - 1 -G3 3 6 6 . 0 8 13 - 3 5 - 6 1 - 8 3 Level girdle 4 6 8 . 54 0 7 - 4 1 - 5 5 - 8 9 I I

5 7 0 . 0 0 0 2 - 4 6 - 5 0 - 94 I I

6 4 1 . 0 6 1 5 - 3 3 - 63 - 8 1 Meet 1 - 1 - 3 - 4 7 4 0 . 2 2 9 6 - 4 8 Meet culet 8 3 9 . 94 2 4 - 72 Meet culet

CROWN A 42 . 9 7 0 2 - 4 6 - 5 0 - 94 Leave some girdle B 4 0 . 8 3 0 7 - 4 1 - 5 5 - 8 9 Level girdle C 4 0 . 9 3 1 3 - 3 5 - 6 1 - 8 3 I I

D 3 5 . 4 9 2 0 - 2 8 - 6 8 - 7 6 I I

E 3 7 . 0 0 9 6 - 4 8 Meet A-A at girdl e F 3 4 . 5 2 0 9 - 3 9 - 5 7 - 8 7 Meet B - C at girdle G 2 8 . 8 6 2 4 - 7 2 Meet D-D at girdl e H 2 1 . 4 6 0 4 - 44 - 5 2 - 9 2 Meet A- B - E - F

' J 16 . 0 7 1 6 - 3 2 - 64 - 8 0 Meet C - D - F - G 0 . 0 0 Table

*OMNI preform i s f ormed by steps 1 -G4 . The girdle l ine wil l not be level unt il steps 3 - 5 are cut .

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OMNI Oval 1 . 5 0 : 1 ( OMOV15 0A . GEM ) by Robert W . Strickland 3 / 13 / 9 8

Angles for R . I . = 1 . 6 3 6 9 facet s + 1 6 facets on girdle = 8 5 2 - fol d , mirror- image symmet ry 9 6 index

April, 1 998

r l L/W = 1 . 5 0 2 T/W = 0 . 8 9 0 T/L = 0 . 5 9 3

P/W = 0 . 6 3 8 C/W = 0 . 1 74 H/W = ( P+ C ) /W+ 0 . 02 = 0 . 8 3 2 P /H = 0 . 7 6 7 C/H = 0 . 2 0 9 Vol . /W�3 = 0 . 45 9

PAVILION 1 42 . 0 0 0 4 - 44 - 5 2 - 9 2 - TCP

12 - 1 8 - 3 0 - 3 6 - 6 0 - 6 6 - 7 8 - 84 2 4 1 . 7 5 2 0 - 2 8 - 6 8 - 7 6 TCP Gl 9 0 . 0 0 2 0 - 2 8 - 6 8 - 7 6 Establ i sh length G2 9 0 . 0 0 12 - 3 6 - 6 0 - 84 OMNI : Meet 1 - 2 - Gl * G 3 9 0 . 0 0 0 6 - 4 2 - 54 - 9 0 OMNI : Meet 1 - 1 -G2 G4 9 0 . 0 0 0 2 - 4 6 - 5 0 - 94 OMNI : Meet 1 - 1 -G3 3 6 5 . 2 6 12 - 3 6 - 6 0 - 84 Level girdle 4 6 8 . 6 6 0 6 - 4 2 - 54 - 9 0 "

5 7 0 . 0 0 0 2 - 4 6 - 5 0 - 94 "

6 4 0 . 9 3 1 5 - 3 3 - 6 3 - 8 1 Meet 1 - 1 - 3 - 4 7 4 0 . 2 3 9 6 - 4 8 Meet culet 8 4 0 . 3 6 2 4 - 7 2 Meet culet

CROWN A 4 7 . 02 0 2 - 4 6 - 5 0 - 94 Leave s ome girdle B 4 6 . 6 0 0 6 - 4 2 - 54 - 9 0 Level girdle C 4 0 . 5 8 12 - 3 6 - 6 0 - 84 " D 3 5 . 8 7 2 0 - 2 8 - 6 8 - 7 6 II

E 4 0 . 0 0 9 6 - 4 8 Meet A-A at girdle F 3 6 . 0 7 0 9 - 3 9 - 5 7 - 8 7 Meet B - C at girdle G 2 9 . 7 0 2 4 - 7 2 Meet D - D at girdle H 2 3 . 6 3 0 4 - 44 - 5 2 - 9 2 Meet A- B - E - F .J 1 8 . 2 6 1 6 - 3 2 - 64 - 8 0 Meet C - D - F - G

0 . 0 0 Table

*OMNI preform is formed by steps 1 - G4 . The girdle l ine wil l not be level unti l steps 3 - 5 are cut .

Page 18

US.F G. Newsletter Vol 8. No. 1 April, 1 998

Old Uncuttable Revisited

by Robert H. Long

After developing the OMNI preforming system, I looked for a good candidate for its application. Since I originally had so much trouble cutting "Old Uncuttable," that design seemed like a good candidate . It turned out to be an excellent choice for replacing the original CAM preform with an OMNI preform. In designing the OMNI preform, the comer facet having the hightest elevation angle in the "Old Uncuttable" design was chosen as the starting point in the preform design. This turns out to be a general rule of thumb in designing an OMNI preform. It will usually provide the most efficient preform, since the starting facet in the OMNI preform is also one of the final facets in the stone. The completed OMNI preform is shown below.

With this prefom, a tiny remnant of one of the preforming facets ( 40.16° 24-72) will remain when all the final pavilion facets are cut. This tiny remnant is shown highlighted by circles in the next picture ( above right). A slight recutting of all the pavilion facets, as will occur with the pre-polish cutting step, should remove this preforming remnant. The presence of this

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ROUGH-CUT PAVILION SHOWING PREFORM FACET REMNANT

remnant of a preforming facet is an indication that the preform is the most efficient possible .

At the request of a reader, OMNI preforms have been calculated for Brilbaro (02 .128) and Ember (04.037). I will be happy to work on any other designs any readers may suggest . Contact me at:

Robert H. Long 2232 78th Ave. S.E. Mercer Island, WA 98040 E-mail: RHLong@msn.com

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Old Uncuttable Revis ited by Robert H . Long

P4 44 . 5 0 1 0 - 3 8 - 5 8 - 8 6 PS 44 . 8 3 0 8 - 4 0 - 5 6 - 8 8 P6 4 3 . 7 8 9 6 - 4 8 P3 4 3 . 12 14 - 3 4 - 6 2 - 8 2 P2 42 . 2 7 1 6 - 3 2 - 64 - 8 0 Pl 4 0 . 1 6 2 4 - 72

9 6 Index L/W = 1 . 4 0 0 0

Page 19

Gl 9 0 2 4 - 7 2 G2 9 0 2 2 - 2 6 - 7 0 - 74 G3 9 0 1 8 - 3 0 - 6 6 - 7 8 G4 9 0 04 - 44 - 5 2 - 9 2 GS 9 0 0 1 - 4 7 - 4 9 - 9 5 G6 9 0 9 6 - 4 8

C /W = 0 . 6 9 3

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April, 1998

Old Uncuttable Revi s ited with OMNI Preform by R . H . Long 0 8 . 045C See attached instructions for more detailed preforming instruct ions .

Angles for R . I . = 1 . 54 113 facets + 2 0 facets on girdle = 13 3 2 - f old , mirror- image symmet ry 9 6 index L/W = 1 . 4 0 0 T/W = 0 . 8 9 7 T/L = 0 . 6 4 1 P/W = 0 . 6 7 1 C/W = 0 . 2 04 H/W = ( P+C ) /W+ 0 . 0 2 = 0 . 8 9 5 P/H = 0 . 7 5 0 C/H = 0 . 2 2 8 Vol . /WA 3 = 0 . 5 5 1

44 . 8 3 0 8 - 4 0 - 5 6 - 8 8 4 3 . 12 14 - 34 - 62 - 8 2 4 0 . 16 2 4 - 7 2

Girdles (Gl -G6 ) wil l not make level l ine on the OMNI pref orm .

PAVILION CROWN Gl 9 0 . 0 0 2 4 - 7 2 a 5 2 . 5 0 0 4 - 44 - 5 2 - 9 2 G2 9 0 . 0 0 2 2 - 2 6 - 7 0 - 7 4 b 4 7 . 5 0 1 8 - 3 0 - 6 6 - 7 8 G3 9 0 . 0 0 1 8 - 3 0 - 6 6 - 7 8 C 5 2 . 0 0 2 2 - 2 6 - 7 0 - 74 G4 9 0 . 0 0 0 4 - 44 - 5 2 - 92 d 5 2 . 0 0 2 4 - 72 GS 9 0 . 0 0 0 1 - 4 7 - 4 9 - 9 5 e 5 2 . 0 0 0 1 - 4 7 - 4 9 - 95 G6 9 0 . 0 0 9 6 - 4 8 f 5 2 . 0 0 9 6 - 4 8 1 44 . 5 0 1 0 - 3 8 - 5 8 - 8 6 From preform g 4 1 . 1 0 0 7 - 4 1 - 5 5 - 8 9 2 4 3 . 0 0 14 - 3 4 - 6 2 - 8 2 Meet corner h 4 0 . 5 0 1 6 - 3 2 - 64 - 8 0 3 5 8 . 0 0 1 8 - 3 0 - 6 6 - 7 8 Level girdle i 3 7 . 0 0 2 2 - 2 6 - 7 0 - 74 4 5 8 . 0 0 2 2 - 2 6 - 7 0 - 74 Level girdle j 3 7 . 0 0 0 1 - 4 7 - 4 9 - 9 5 5 5 7 . 5 3 2 4 - 7 2 Level girdle k 3 7 . 6 0 1 0 - 3 8 - 5 8 - 8 6 6 6 1 . 5 0 0 4 - 44 - 5 2 - 9 2 Level girdle 1 3 7 . 8 0 14 - 3 4 - 6 2 - 82 7 6 3 . 7 8 0 1 - 4 7 - 4 9 - 9 5 Level girdle m 3 7 . 0 0 9 6 - 4 8 8 6 3 . 3 2 9 6 - 4 8 Level girdle n 3 7 . 0 0 2 4 - 72 9 4 1 . 8 5 1 6 - 3 2 - 64 - 8 0 Meet 2 - 3 - 4 0 2 2 . 0 0 0 1 - 4 7 - 4 9 - 9 5 1 0 44 . 5 0 0 8 - 4 0 - 5 6 - 8 8 Meet 1 - 6 - 7 p 2 2 . 0 0 9 6 - 4 8 11 4 0 . 0 0 1 8 - 3 0 - 6 6 - 7 8 Meet 4 - 5 - 9 q 2 2 . 0 0 2 2 - 2 6 - 7 0 - 74 12 4 3 . 0 0 0 6 - 4 2 - 54 - 9 0 Cut to PCP r 2 2 . 0 0 2 4 - 7 2 13 3 9 . 64 2 1 - 2 7 - 6 9 - 7 5 Meet 4 - 5 - 9 - 11 0 . 0 0 Table 14 4 5 . 2 0 0 3 - 4 5 - 5 1 - 9 3 Meet 7 - 8 - 10 - 12

Page 20

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OMNI Egg Brilliant ( OMNIEGG . GEM ) by Robert W . Strickland 4 / 2 / 9 8

Angles for R . I . = 1 . 54 7 1 facets + 16 facets on girdle = 8 7 1 - fold , mirror- image symmetry 9 6 index L/W = 1 . 24 1 T/W = 0 . 7 3 9 T/L = 0 . 5 9 5 P/W = 0 . 5 6 2 C/W = 0 . 1 0 6 H/W = ( P+ C ) /W+ 0 . 02 = 0 . 6 8 8 P/H = 0 . 8 1 7 C/H = 0 . 154 Vol . /W

A3 = 0 . 2 9 9

PREFORM ( See page 2 8 ) 4 3 . 0 0 0 3 - 0 7 - 13 - 17 - 2 6 - 3 3 - 4 1 - 4 6 - Meet TCP

5 0 - 5 5 - 6 3 - 7 0 - 7 9 - 8 3 - 8 9 - 9 3 9 0 . 0 0 0 3 - 9 3 Set s i z e GS 9 0 . 0 0 2 7 - 6 9 9 0 . 0 0 0 9 - 8 7 Meet 1 - 1 -Gl G6 9 0 . 0 0 3 1 - 65 9 0 . 0 0 15 - 8 1 Chain res t G7 9 0 . 0 0 3 6 - 6 0 9 0 . 0 0 2 2 - 74 GB 9 0 . 0 0 4 3 - 5 3

PAVILION CROWN 2 65 . 4 6 0 9 - 8 7 a 3 2 . 1 0 0 3 - 9 3 3 6 6 . 5 7 1 5 - 8 1 b 3 1 . 8 3 0 9 - 8 7 4 6 8 . 7 6 2 2 - 74 C 3 0 . 9 1 15 - 8 1 5 7 0 . 0 0 2 7 - 6 9 d 3 0 . 8 8 2 2 - 74 6 6 9 . 84 3 1 - 65 e 3 2 . 63 2 7 - 6 9 7 6 8 . 3 7 3 6 - 6 0 f 3 0 . 1 7 3 1 - 6 5 8 6 5 . 8 0 4 3 - 5 3 g 2 9 . 0 9 3 6 - 6 0 9 4 1 . 94 1 0 - 8 6 h 2 5 . 9 0 4 3 - 53 1 0 4 1 . 3 6 3 7 - 5 9 i 2 0 . 2 3 4 8 1 1 4 1 . 0 7 2 1 - 7 5 j 2 4 . 8 3 3 3 - 63 12 4 1 . 9 8 9 6 k 2 6 . 5 0 2 4 - 72 13 4 2 . 2 9 4 8 1 2 6 . 0 0 12 - 84

m 2 6 . 2 7 9 6 n 15 . 3 4 0 6 - 9 0 0 14 . 3 6 1 9 - 7 7 p 14 . 4 7 2 9 - 6 7

q 1 1 . 5 7 3 9 - 5 7 t 0 . 0 0 Table

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OMNI Shield ( OMSHLD . GEM ) by Robert W . Stri ckland 9 / 1 / 9 7

Angles for R . I . = 1 . 54

r l

5 5 facets + 13 girdles = 6 8 mirror- image symmetry 9 6 index

---W'---

L/W = 1 . 14 3 T/W = 0 . 6 6 8 P/W = 0 . 5 4 8 C/W = 0 . 1 1 9 H/W = ( P+C ) /W+0 . 02 = 0 . 6 8 8 P /H = 0 . 7 9 7 C/H = 0 . 17 3 Vol . /WA

3 0 . 2 8 3

PAVILION 1 42 . 0 0

Gl 9 0 . 0 0 G2 9 0 . 0 0 G3 9 0 . 0 0 G4 9 0 . 0 0 GS 9 0 . 0 0 G6 9 0 . 0 0 2 6 7 . 6 0 3 6 9 . 0 0 4 7 0 . 0 0 5 6 8 . 5 0 6 7 0 . 0 0

0 2 - 0 8 - 14 - 2 2 - PCP 3 1 - 3 6 - 4 3 - 5 3 -6 0 - 6 5 - 74 - 8 2 -8 8 - 94 0 8 - 8 8 Note 1 1 2 - 84 Note 2 1 6 - 2 0 - 7 6 - 8 0 II

2 4 - 7 2 II

3 6 - 6 0 I I

4 8 II

0 8 - 8 8 Level girdle 12 - 84 II

1 6 - 2 0 - 7 6 - 8 0 II

2 4 - 7 2 II

4 8 II

CROWN A 3 5 . 8 0 B 3 5 . 5 0 C 3 5 . 8 0 D 3 6 . 5 0 E 3 6 . 6 0 F 3 7 . 10 G 3 5 . 7 0 H 2 4 . 5 0 J 3 1 . 0 0 K 3 1 . 0 0 L 2 4 . 9 0 M 14 . 6 0 N 1 7 . 0 0 p 13 . 7 0 Q 1 3 . 2 0 R 1 3 . 7 0 T 0 . 0 0

0 8 - 8 8 1 2 - 84 1 6 - 8 0 2 0 - 7 6 24 - 7 2 3 6 - 6 0 4 8 44 - 5 2 2 2 - 74 14 - 8 2 9 6 1 0 - 8 6 1 8 - 7 8 2 6 - 7 0 4 0 - 5 6 4 8 Table

April, 1998

Breaks " It

It

" II

It

Mains I I

I I

I I

S tars II

II

II

II

Note 1 . Facets Gl and G6 are cut at about the same mas t height , so rough- in Gl (pointy end ) and G6 ( flat end ) f irst to s i ze the stone .

Note 2 . Steps 1 -G6 comprise an OMNI preform . The girdle l ine wil l not b e l evel unti l steps 2 - 6 are cut . See page 2 8 .

Page 22

US.F G. Newsletter Vol 8. No. 1 April, 1998

Tips for Gemstone Microphotography

by Scott and Susan Wilson

From New Mexico Facetor's Guild Newsletter,

July-August 97

INTRODUCTION Pick up any issue of the Journal Gems and Gemol­

ogy and you will see beautiful close-up photographs of faceted gems. It is natural, and probably correct, to presume that these photographs were taken with specialized, expensive equipment and setups. We describe some techniques that obtain comparable results with ordinary cameras, film, and some inexpensive accessories.

To take quality gemstone photos requires considera­tion of the following aspects:

1 . Camera, Lens, and Tripod 2 . Film 3. Illumination 4. Magnification 5. Stone preparation 6. Stone mounting and support 7. Exposure and Depth of Field 8. Processing

If one takes the time to consider each of these items, it is actually quite easy to come up with excellent photo­graphs of your stones.

It is clearly not possible to address these topics in complete detail in this forum, so for in-depth informa­tion you might want to consult a good book on the subject. We recommend Photographing Minerals,

Fossils, and Lapidary Materials by Jeffrey Scovil (Geoscience Press, Tucson, AZ, 1996. ISBN 0-945005-21-0, about $40). This book covers lots of territory and is very readable. It does not, however, contain some of the tricks we are about to offer! We'll hit just some highlights here.

CAMERA AND LENS A 35mm SLR camera with through-the-lens (TTL)

exposure metering is almost a necessity unless you are well versed in the intricacies of exposure calculations. TTL metering makes it much easier to obtain a proper

exposure. You'll also need a way to obtain magnifica­tions so that your stone fills between 50% and 75% of the field of view. This can be done in one of two ways: Cheap:

Use your normal camera lens, but get some exten­sion tubes from a camera store. These tubes, made specially for each type of lens mount, space the lens from the camera body. This greatly increases the magnification. It also reduces the amount of light that gets in, resulting in longer exposures (not a major problem).

More expensive: Get a macro lens for your camera. A plain macro will give much better image quality than the more common zoom-macro lenses. Macro lenses can be expensive though, so give a zoom-macro a try if you have one.

We have used a Canon AE-1 body ( old technology by current standards) with the standard 50 mm lens and 50 mm extension tube and obtained good results. This combination gives sufficient magnification to fill 75% of the field of view with a 10 mm stone.

Make sure that you use a remote shutter release. This is a little cable with an actuator on the end that attaches to the shutter release on the camera. It allows you to release the shutter without jiggling the camera, and is essential for obtaining sharp pictures.

Use a tripod. Make sure it's rock solid. You may find it convenient to set up the tripod so that the camera points down at the comer of a table for your work. This lets you place the lamps on the table, along with the stone mounting arrangement, while keeping the tripod stable on the floor.

FILM Film selection is a bag of worms. There are

questions regarding color balances (daylight vs. flash), speed, slide vs. print, etc. For our purposes, we found that ordinary 200 ASA Kodacolor Gold print film provides acceptable results with tolerably long exposures. You may need to experiment a bit depending on the color of your stone and your camera/lens/lighting setup.

If you are using extension tubes to get magnification, you'll have a difficult time getting enough light on the

Page 23

U.S.F. G. Newsletter Vol 8. No. 1 April, 1998

subject to use film slower than 200 ASA. Stick with reasonably fast film to make your exposures easier to take.

ILLUMINATION

The exact illuminations setup is best determined essentially by trial and error. Look through the viewfinder at your stone while it is in the position for being photographed, and adjust the lights (use an assis­tant) until you get pleasing results. Pay attention to

Professional mineral photographers have a whole strong shadows ( either minimize them or use them array of lighting sources and arrangements at their creatively), highlights within the stone, and hot spots disposal. They select the lighting to highlight aspects of (very strong, annoying reflections from a facet). This the specimen being photographed, and often use a combination of a light box (a box with a translucent top upon which the specimen rests, lit from below), direct lighting, and diffuse lighting.

You might expect that some kind of light that illumi­nates the stone from all points in a circle around the lens might produce good results. Such a light is called a ring light and is used often in industrial inspection. They generally don't do well for gemstone photography because they make the stone look flat and lifeless.

We found that a small incandescent table lamp with a non-patterned, white shade, and a bright Tensor-type light are sufficient to get nice photos of faceted stones. Avoid fluorescent lamps as they flicker on and off 120 times per second, faster than you can see, but often sufficient to confuse your camera's exposure meter. Fluorescent bulbs also have a different color spectrum than tungsten incandescent bulbs, and this may throw off the color balance.

If the lamp has an adjustable intensity, it is best to set the intensity near the maximum level and leave it there, adjusting the amount of light that falls on the stone by backing the light away from the stone. The reason for leaving the power level fixed is that the color spectrum of the light produced by the lamp may change greatly depending on the power setting, and you want the color spectrum to remain constant for all your exposures to preserve whatever color balance you have available.

The Tensor light should in general be very close to the lens barrel to get nice internal reflections in the

�tone. Make sure that you don't start to heat up the lens though! The table lamp can be moved around to provide some balance and overall illumination, perhaps highlighting a specific internal reflection or producing a pleasing illumination gradient on the background.

takes time, but remember that the camera will see exactly what you see in the viewfinder, so make the time investment.

MAGNIFICATION As mentioned above, you generally will want a

single stone to span 50-75% of the field of view. If you use too little magnification, your stone will be difficult to appreciate in the photo. Too much magnification starts to bring out imperfections in the stone and dust on the surface of the stone. Unless you are trying to photograph the inclusions in your stone, don't push the magnification too far. High magnification also brings out dust on the surface, and can also reduce the depth of field so much that it becomes impossible to have the table and back facets in focus at the same time.

STONE PREPARATION The crown and pavilion of your stone must be

absolutely clean. This includes dust, which is a real irritant in this type of photography. Use whatever magic recipe you customarily employ to clean a stone. Use of lens tissue is recommended to move the stone to its mount and arrange it there. Use of gloves is generally a waste of time due to the lint and dust that is produced. Anti-static precautions may be helpful to keep dust from settling on or near a freshly cleaned stone.

Be especially wary of tiny water spots that may appear when using typical 70% isopropyl alchohol to clean the stone. The alcohol may evaporate, leaving the water behind as very tiny droplets. These droplets will cause the surface to look slightly fuzzy and will cause the stone to look less brilliant than it should. Instead, find some 91 % isopropyl alcohol. It should be available in well-stocked pharmacies. The reduced water content eliminates this problem. (As a side note, this can also be a problem when cold <lopping since the water droplet

Page 24

US.F. G. Newsletter Vol 8. No. 1 April, 1998

steady hand for placing the stone--make sure the stone can't fall on something hard if it falls off the needles) but the results are worth it !

Take your time with the lighting. Try lots of varia­tions in light position and intensity while looking through the viewfinder. Don't forget about the background and possible shadows that may fall on it and appear as out-of-focus blobs in your photo. You will eventually find a combination that is nearly breathtaking!

EXPOSURE AND DEPTH OF FIELD Getting the exposure right can be a bit tricky. You

want to accomplish a number of things at the same time:

1. Getting the right amount of light in to make the exposure.

2. Keeping the depth of focus long enough to have the whole stone (table down to pavilion) in focus, but not enough for the background to be in focus.

3. Keeping the exposure short enough to avoid

reciprocity failure--this happens when you try to use the film outside its design exposure limits, and shouldn't be a problem until you start getting exposure of several seconds (for ASA 200) or longer.

The depth of field is greatly influenced by the aperture setting. A large diameter aperture ( small aperture number) will give a short depth of field, and a small diameter aperture (large aperture number) will give a long depth of field. The depth of field is the distance parallel to the lens axis over which the subject will be in focus. You will have to play with your setup to find the best aperture setting; we found that we needed about an £'5.6 aperture to get the correct depth of field. Note that on automatic cameras, you must find a way to keep the aperture fixed and vary the exposure using the exposure time.

Set the exposure time so that the camera thinks it has a ''normal" exposure. Often, this means that the TTL metering should indicate 5.6. Note that you may need to find out how your camera ''weights" the picture

for its exposure calculations and make appropriate adjustments.

In general, it is best to "bracket" your exposures by one stop. This means that you take a picture at one stop underexposed ( via the exposure time, not the aperture, to avoid changing the depth of field), and one stop overexposed, as well as normal exposure. Keep a log so that you know what your exposure conditions were for each picture you take--this information is vitally important when you get your photos back and want to know which combination worked the best.

When you snap a picture, make sure that the table and tripod are both steady. Use the remote shutter release to gently take the picture. Make sure that the table and tripod aren't vibrating during the exposure, such as might be due to a nearby refrigerator, dishwasher, or overly interested pet.

PROCESSING Even if you do everything right, the processing can

still make the difference between success and failure. The developing of the film itself is a simple matter

-the processor will dip the film in various chemicals according to a recipe from the manufacturer and that's about the end of it.

The printing is where some additional trickery needs to happen. First of all, avoid mail-in processing (as opposed to one-hour type service) at first. Mail-in processing is generally done fully automatically with no person ever coming into the loop. One-hour processing normally has a person sitting at the machine to make the exposures during printing. Find a processing center you can trust (and not go broke with) and talk to the operator who will print your photos. Tell them that your pictures are of a technical nature, not scenery, and that you may need them to adjust the "density." Suggest that they start out at "plus one density" and adjust further if necessary. The density is similar to the exposure that you made with the camera, only now the exposure is applied to the print, not the film.

You might also want to tell them what colors they should see, so they can balance the color to some extent for you. Tell them that you have bracketed the exposures and which ones are plus one and which are

Page 25

U.S.F. G. Newsletter Vol 8. No. 1 April, 1998

.__(\_;:;;;;;,-:;;:: ; ;_t�_····�_:_·: : :_. ___. 7 � ''Tensor" lamp

f Depth of Field ..- Stone

..- Needle

film will keep the adhesive from properly bonding to

the stone! )

STONE MOUNTING AND SUPPORT

Stone mounting and support is one of the things that

really makes a difference in the quality of the photo.

Some common ideas are:

Black Velvet:

One might think that resting the stone on a piece

of clean black velvet would be just the trick. In

practice, you will find that the little hairs that

make the velvet will glisten and make a very

distracting background. The velvet backing will

also show through as a distraction.

Modeling clay or some kind of putty:

No matter how small you make the clay wad, it

will show through on the pavilion. It will also

droop while you are working.

Black Paper:

The grains and fibers in the paper will show up

as a distracting background.

Toothpicks and paper clips:

These invariably end up being visible either

through the stone, under the pavilion or stick out

from behind the stone.

Professionals will often use a piece of glass upon

which to rest the stone. If done right, and you have paid

particular attention to reflections in the glass, this can

work well. Many photos in Gems and Gemology are

done this way. Sometimes a special kind of very black,

fine-grain paper is also used to rest the stone on and

also to form a backdrop. This too can be very effective,

particularly if you want to light the backdrop to

enhance the stone.

We have found that by using the reduced depth of

field that results from magnification, it is possible to

make a support that is almost invisible and has no

background pattern whatsoever. (Depth of field is influ-

enced by exposure setting-:--See next section.) It also

lets one apply light through the bottom of the stone to

enhance its brilliance. The trick is to make a setup like

the one shown above. Here, a piece of black velvet or

other backdrop is placed over a small slab of stiff Styro­

foam. A set of three or four long ( several inches), thin

needles (depending on your stone geometry) is inserted

through the backdrop, into the foam. The needles are

kept vertical and parallel to each other, and the ends are

adjusted to provide discrete points on which to rest the

stone.

By setting the stone on the ends of the needles, and

looking straight down with the camera, the needles

cannot be seen and the ends, being so small, disappear

in the reflections internal to the stone. The backdrop is

very much out of focus due to the limited depth of field,

and so it doesn't add distracting patterns of its own.

This technique takes some time to get used to ( and a

Page 26

US.F. G. Newsletter Vol 8. No. 1 April, 1998

minus one stop. This may help them determine how to get the best results. If the operator ignores you or doesn't understand what you are saying, find a different processing center. You will eventually find one that is willing to work with you.

Additionally, you may want to purchase an 18% gray card from a photo or art store, and take a picture of it in the same configuration used for photographing your stones. A gray card is printed to have a controlled reflectance and color. Take a picture of the card ( or the corner or a piece of it since they are usually 8x 10 inches) as the first exposure. Tell the processing opera­tor that the first photo is an 18% gray car and they may set the machine to give approximately correct color balance even if your lights and film aren't matched. This will hopefully make the color of your stones in the prints come out close to their actual color. This is not entirely foolproof though, and you'll have to experiment to get the best results.

As you become more familiar with how it works and what to ask for, you may find that some mail-in or drop-off processing facilities will let you include special instructions that will suffice for your needs at a reduced cost relative to one-hour processing.

CONCLUSION Expect to spend at least 10 minutes on each arrange­

ment of the stone. We suggest using 12 exposure rolls to facilitate getting feedback on your work. Using your log book (you did keep one, didn't you?), see which combination of settings works the best. You will still need to bracket your exposures, but you will at least know where to start.

Using the general guidelines given here, you can expect to get some high quality photos. Experiment and try out new ideas and you will be rewarded! D

What is a Tier?

by Fred Van Sant

Charles Moon asked me to please write about sets and tiers. In the USFG Faceting Dictionary we find, "A tier of facets consists of a group of facets at the same elevation around the stone. It may be made up of one or more sets of facets."

My understanding is that the word "tier" was first applied to Step Facets, where level lines occurred end-to-end around the stone. Later it was used more loosely-there did not have to be a level line clearly marking off one tier from another, but one or more sets of facets could be easily seen to make a group at the same rough elevation. Certainly all facets meeting at a culet point could be considered a tier. Likewise all girdle facets are a tier, and so are all break facets which form the girdle. On an SRB crown, the breaks are a tier, the mains another, and the stars another. Elevation refers to distance above or below the girdle when looking at a side view of the stone on a diagram sheet. Difference in elevation is the key in determining a tier of facets.

A set of facets is whatever is listed as a set in the List of facets on the diagram sheet. Sometimes this seems quite arbitrary to the cutter, as when the designer lists four facets as one set to make the culet point, and twelve more at the same angle to meet at the culet. This is usually done because the designer thinks he is giving the best set to make the culet-facets which are well separated in indexing, to prevent the beginner from using other facets whose indices are too close together.

The term "intermediate" applies to all facets wqich do not meet at the girdle, nor the culet point on pavilion, nor the table on the crown. D

Page 27

US.F. G. Newsletter Vol 8. No. 1 April, 1998

Preforming and Pavilion Rough Shape by Fred Van Sant

In deciding what design to use to cut a stone, the rough shape of the pavilion area shou ld be assessed. Aside from plan view shape, there are also the side-view profi les to be considered, as il lustrated in Figures 1 -3 , and it is these which are to be discussed.

Some designs can be preformed in a variety of ways, and the diagram sheet usual ly does not show all of them. Any design you plan to cut should be studied for other methods.

Preforming by measurement, or CLAM, can be done on any shape of rough , but they apply to preforms starting with girdle facets. Here we will be considering only preforms starting at the cu let :

CAM Preforms: For purpose of discussion let's assume an average CAM angle of 35° and pavilion of 41 °. Figure 1 shows a good profile for a CAM preform. There is plenty of width near the bottom for the CAM angles to reach the edges of the stone where the girdle will be, without sacrificing vert ica l l y .

Fig . 1

In Figu re 2, CAM angles of 35° wil l reach the edge of the stone short of its full width, so the stone wil l be smaller in its plan view size

CAM

Figures 2 and 3 are the same profiles. They are closer to what the finished pavilion wi l l be like. In 2 there is enough material for the crown but only by sacrificing stone width. In 3 the fu l l width is obtained but there's not enough material for the crown. So in this case the CAM Preform is to be avoided if possible. For maximum yield this profile calls for some method other than CAM.

Fig . 3

In general , if after grinding a flat spot for the table, the side-view shape is close to the finished stone shape, avoid the CAM Preform. Use CAM only where you have the ful l stone width about halfway to the culet from proposed girdle line. Let the stone be your guide.

TOP S I DE 48

54 42

66 30 I 72 24 L

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BOTTON

Page 28

CREDITS FOR SINGLE STONE DESIGNS

NOVICE DESIGN - "North Puget Sound Faceting Guild Logo Design" . During the 1991 Northwest Facetors' Conference N�rm Steele demonstrated facet deignin� usmg GemCad computer program. He showed the versatility of the program by taking the design for our logo and determining the angles that will give maximum brightness. For example, the angles previously given showed a brightness of 36 using the raytracing program. The new angles show a brightness of 96.

�VANCED DESIGN - "Windmill" By Jim Spence was published in the USFG Newsletter, July-Sept 1996.

CHAMPION DESIGN - "Nulli Secundus" By Bill Stanoyev, B.C. Canada Faceters' Guild - Angles, March 1988.

PAST CHAMPION DESIGN - "Chapco's Stars" By Charles Coville, this is one of a se?es of Chapco' s Stars by Charles. This one published in Faceters Gem Cuts Volume 3, 1987.

Make plans now - It's not too early! NW International Faceting Conference

May 22, 23 & 24th 1998 The annual Northwest International Faceting Conference will be held in Mount Vernon, Washington on Friday, May 22, Saturday, May 23 , and Sunday, May 24, 1998. Hosted by North Puget Sound Faceting Guild. The following experts are scheduled to participate: LARRY WINN - Grand Junction, Colorado Featured in the December, 1996 Lapidary Journal for award winning stones with flat, curved and carved facets. DR. JOHN EMME'IT - Brush Prarie, WA successful methods of improving color and clarity in gemstones with treatment.

ROGER FROST - Seattle, Washington will discuss and demonstrate various instruments used to identify gemstones. ROBERT LONG - Mercer Island WA will discuss the "Omni Preform" system and answer your questions. MARIE-CLAIRE DOLE - Mt Vernon, WA She will present a slide program about using gems in metalwork and custom designing. CARL UNRUH - Port Townsend, WA He will discuss how and why cutting decisions are made for gem recovery. CLIFF JACKSON - Burley, Idaho If Cliff can make it he will talk about his "Breakaway Cuts" with curved girdles. CWFG - Portland, Oregon will present the " 12 - Best Designs published in 1997" DEALERS: ALPHA SUPPLY - equipment

B & B GEMS - gem rough

US.F. G. Newsletter Vol 8. No. 1 April, 1998

- 3 -

A C C O M M O D A T I O N S

All within 1/ 2 mile . Make your own arrangements .

COTTONTREE INN , 2300 Market St . , Mt . Vernon , WA 98273 ( 360 ) 428 -5678 Conference Headquarters $62 . 00 + tax , S ing le Occupancy , $67 . 00 + tax , Double

DAYS INN , 2009 Ri vers ide Dr . , Mt . Vernon , WA 98273 ( 360 ) 424-414 1 $45 . 00 + t a x ( 1 bed ) , $55 . 00 + t�x ( 2 beds )

TULIP VAL LEY INN , 2200 F reeway Dr . , Mt . Vernon , WA 98273 1-800-599 -5969 $50 . 00 + tax ( 1 queen bed ) , $55 . 00 + tax ( 2 beds )

COMFORT I NN , 1910 Freeway Or . , Mt . Vernon , WA 98273 ( 360 ) 428-7020 $49 . 00 + tax , Sing le Occupancy , $59 . 00 + tax , Double , $75 . 00 + tax , Suite

R IVERBEND R . V . PARK , 305 W . Stewart Rd . , Mt . Vernon , WA 98273 ( 360 ) 428-4044 F u l l service a v a ilable $ 18 . 00 night

NORTHWEST FACETING CONFERENCE ADVANCED REGISTRATION

Name ( s ) --------�------------�------------�------------�------------� Address

Zip --'----State

Guild/ C lub ------------------------------------------------�------------� Advanced registration is $70 . 00 ( $7 5 . 00 at the door ) per person . This includes the Awards Luncheon . Awards Luncheon ( for spouses not participating in the conference ) is $17 . 50 .

CONFERENCE REGISTRATION - Number o f people ------------------AWARDS LUNCHEON ONLY - Number of people ------------�---------Enclosed is my advanced registration check for $

---------

Please send ad vanced registration card & check to : Bev Dillon 909 Carter Rd . Sedro Woolley , WA 98284

For F urther Informe1t i on ca l l Conforonce Chn i rman , Carrol 1 D :i 1 l on ( 360 ) 85G-55Hl

US.F. G. Newsletter

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Novice Design to be faceted in any Quartz Minimum across flats 1 0mm Maximum across flats 12mm

(Always adjust indexing and angles to get good meets)

96 90 6

54 42 48 .

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TOP

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PAVIL ION

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5 2 - 6 0 - 6 8 - 7 6 - 8 4 - 9 2 3 4 0 . 0 0 9 6 - 3 2 - 64 Meet ( Pl - P2 - P2 ) 4 4 2 . 0 0 1 6 - 4 8 - 8 0 Meet ( P2 - P3 - P2 )

CROWN

1 5 5 . 0 0 9 6 - 1 6 - 3 2 - 4 8 - 6 4 - 8 0 Fix girdle width 2 3 0 . 0 0 0 4 - 1 2 - 2 0 - 2 8 - 3 6 - 44 - Meet ( Cl -Cl - girdl e

5 2 - 6 0 - 6 8 - 7 6 - 84 - 9 2 3 2 8 . 0 0 9 6 - 3 2 - 64 Meet ( C2 - Cl - C2 ) 4 3 0 . 0 0 1 6 - 4 8 - 8 0 Meet ( C2 - C2 - C3 ) 5 0 . 0 0 Table Meet ( C3 - C2 - C2 - C4 )

FACETS February 1998

TOP

l.8

24

30

NORTH PUGET S6UND FA.CETING G.UILD

Nulli ·Secundus

6

42

FACETS

Champio� Design to be faceted in any Topaz Minimum across 96 - 48index . 12mm · Maximum across 96 - 48 index 1 5mm

(Always adjust indexing and angles to get good meets)

96 90

5 4 48

PAVI LION

l 4 0 . CJ O

3 4 0 . 7 2 2 4 1. . 0 0

6 5 0 . 0 0

9 0 . 0 0 4 4 0 . 9 1 5 4 1 . 2 5 7 4 2 . 3 6

9 0 . 0 0 B 7 3 . 7 1 9 4 2 . 3 7 1 0 4 0 . 8 2 1 1 4 0 . 7 3 1 2 4 0 . 8 9 13 54 . 3 0

9 0 . 0 0 1 5 6 1 . 4 ·1

1 6 4 0 . 7 2 1 7 4 0 . ;1 0 1 8 4 4 . 94 14 52 . 2 6

7 8

72

66

:I...

i 1 0 8

. l./lJ/ p

ir\ �14 1 l.5 -·..._� .l!�

BOTT On END

7 0 face t s i 7 facets on g irdle = 7 7 1 · f o ld , l!a rror- image symmec ry 9 6 index L/W 1 . 0 3 8 T/W = 0 . 6 2 1 T/L = 0 . 5 9 8 P / W � 0 . 4 5 8 C/W = 0 . 13 3 H/W = ( P� C ) /W+ 0 . 0 2 = 0 . 6 1 1 P / H = 0 . 1 4 9 C/H 0 . 2 1 8 Vol . /W" 3 = 0 . 2 1 9

CROWN 9 6 - 1: - 2 8 - 4 2 - 54 - b S - 6 4 0 2 - 1 0 - 8 6 - 94 3 45 . 0 0 4 2 - 54 04 - 0 8 - 8 8 - 9 2 2 4 5 . 00 2 8 - 68 96 - 1 2 - 8 4 l 4 5 . 0 0 9 6 - 12 - 84 9 6 - 12 - 8 4 6 3 0 . 00 4 2 - 54 1 4 - 8 2 5 3 0 . 00 2 8 - 6 8 1 6 - 8 0 4 3 0 . 00 9 6 - 1 2 - 84 2 2 - 74 9 1 5 . 00 4 2 - 54 2 8 - 6 8 8 15 . 00 2 8 - 6 8 2 8 - 6 8 7 1 5 . 00 96 - 1 2 - 84

24 - 7 2 Table 0 . 0 0 3 0 - 4 0 - 5 6 - 6 6 3 5 - 6 1

3 8 - 5 8 3 5 - 6 1 4 2 - 5 4 4 2 - ':, 4 4 4 - 5 2 4 6 - ':> 0 4 6 - � 0 3 8 - 5 8

February 1998