CRYSTALLOGRAPHY OF CALCITE FROMLAKE SUPERIOR COPPER MINES

Csanrps Palacnr,E ara ar il U nh er sity, C ombrid, ge, M a s s achus elts*

In 1898 the writer published a paper (palache, 1898) on the crystal_lography of Lake Superior calcite. Aithough a large number of new cal-cite forms were described and illustrated in this paper, the measurementsupon which they were based were omitted; the statement made there(page 183) that the observational data for the new forms would appearshortly in the Zeitschrift fiir Krystallographie was never justified by ful-fillment of the promise. However, twenty-four of the thirty-two formsthen proposed were included in the winhel,tabelten of. y. Goldschmidt(1897), with calculated position angles, much of the study having beenconducted in his laboratory. The figures were all reproduced in the sameauthor's Atlas d,er Krystalfformen,Yol. II, Plates II2-1L4, figures 1887-1910 .

The author can ofier no adequate excuse for this failure to publish hisobservations save the fact that the study continued from year to yearas new and often very interesting material came into his hands. Thesummer of 1906 was partly spent on the Copper Range, examining thelocal collections and collecting material for an intended study of thelocal mineralogy, which was never completed. Again in 1920 and l92Ithe author worked with the group of geologists who gathered the ma-terials fot u . s. G. .s. Professional Paper 144 on the copper deposits anclthus collected at first hand a great variety of calcite crystals. A papercontaining all the results and elaborate zonal discussion of the forms wasprepared but for forgotten reasons was never sent to press.

This paper is now presented in abbreviated form after a review of theolder results and an examination of new crystals. The paper of 1g9gmay still serve as giving an adequate general description of the occur-rence of calcite in the Lake Superior region.

Table 1 contains a list of 138 forms found on the nearly 200 crystalsmeasured-a number which may be compared with 82 forms found onthe 150 crystals described in the first paper. This increase shows howenormously rich and varied in development these crystals really are.The last column of the table states the number of crystals on which eachform was observed and may serve as sufficient description of their rera-tive importance. Those forms preceded by an asterisk were new for

* contribution from the Department of Mineralogy and petrography, Harvard uni-versity, No. 260.

.to CHARLES PALACHE

calcite in 1898, or have since been discovered; they number thirty-two

and are collected in Table 2 together with the observed angles, range'

and calculated position angles. These forms vary in importance from a

few which are characteristic for the region and have since been found

elsewhere, to the other extreme of purely local development. They will

be briefly described in the order of enumeration.

Tasr,B 1. Fonus Fouwn oN Laxl Surnmon Car-crtn

Bravais Mi l ler Bravais Miller

No.of.

xls.

No.of

x ls

1 1 T 4 5t7 . r 7 . 19 1s 5 6 1

0 2 2 r0 . r2 .12 .50 . 1 1 . T r . 4

0. 13 . T3. 1 14 .14.250 .14 .1 - ; I . 1 5 5 It 3 . r1 .T4 .2 13 .0 .TT

78 4.80 F.82 6 .

I o 0 0 0 1 1 1 1 5 72 a l l 2 0 1 0 T 1 13 b 1 0 T 0 2 1 1 7

1

1

1

z5

21I

9II

0 3 3 1 4 4 50 7 7 2 s s 40 4 4 | 5 5 7

o 7 7 r 8 . 8 . T 30 8 8 1 3 3 50 . 1 1 . T 1 . 1 4 4 7

I .A .@.

o.[ .

C.o.

T T .

7 - .

t :Q iD ,

p i

J . ,

.ty':T :

ID:

M :

6 'M:

i l :

oL :x.

838687

929396

9899

1 1 3

t l t

1 1 9122

t25129133

32

1 A

2L

L

5o

.)t 2 l

I

6128

J I

1I

9 4 437 .17.n19.9- .9 -

1 1 03 3 1ss2

r t 2 32 2 4 3r t 2 r4 4 8 316.16.32.92 2 4 r

8 . 8 . T 6 . 31 0 1 12 0 2 t

5 0 5 24 0 4 r10 .0 . r 0 . 1

s a 2 1 3 0 5 1 46 | 3 1 4 0 7 2 5s

' , t 10.1.T1.0 7

-3 4

5 0 4 27 3 0 34 0 3 1

7 0 5 119 .0 .13 13 0 2 r l

17 .0 .T1 21 r .o .7 49 r 4 1

5 0 3 1 01 1 . 4 . 0 38 1 3 6

9 r 71 0 05 T T

4 I T3 1 7

0 8 8 7 5 5 3 1 20 6 6 5 l r . r r . 7 30 5 5 4 s 3 2 3

0 4 4 3 7 7 8 80 7 7 s 4 4 , 3 50 3 3 2 5 5 4 7

0 . 1 1 . I T . 7 6 6 5 1 00 . 1 3 . T 3 . 8 7 7 6 60 7 7 4 1 1 . 1 1 . T 0 1

2 t o3 1 14 r 2

s 1 319 .3 .T3/ l J

91 112

13l4*r.)

t 72628

293140

13 .0 .T3 .118 .0 .T8 .128 .0 .n .1

o l r 20 4 4 50 7 7 8

5 4 9 14 . 3 . 7 . r O4 3 7 r

7 .s .Tz 219.13.32.63 2 5 r

r7 .rr .28.6rr.7 .'18.48 . s .13 . 6

5 s 8 27 .4 .11 .1s/ . 4 . r r . o

T

v

d

€

"Yp.R.

K.|n.

I .U .

v ,

t 5 J

136*t J I

1 A 1

425*I 51*

I J.t

M6155

7 .4 .11 .s 7 0 49 .s . I I . 3 26 .1 .1620 .11 .31 .15 22 .2 .9

1 s . 8 . 2 3 . 1 0 1 6 . r . 74 2 6 3 t 3 . r . 519.r0.29.6 18.T.TI

37.r9.56.2r 38.1.1817.9.26.8 17.0.98 . 4 . T 2 . 7 9 1 3

43 s.45 a.48 z.

55 6 .58 n '61 0.

646566

o /6870

n 1

73

CALCITE FROM LAKE SUPERIOR COPPER MINES

Tasrn l-continucd

J /

Bravais Miller

No.of

xls Bravais Miller

No.ofxls

1.59160*161

r62165453+

455+180181

183*189190*

191194196

1972032044

2062 t l2t4

2t52 1 7219

220221*222

))L*

501*226*

227*229+231+

<o 1+

232*233+

1 9 . 1 . 82 5 . 1 . T 1J / . r . I /

2 0 11 s . T . 929.3.r1

4 0 74 I 26 0 7

19.5.9-8 1 0I I . J . D

9 1 02s .7 . 111 7 . o . 2

7 2 338 .1 .3 -8 2 3

31 .9 .13t l . D . l

10 .3 .4

25.7.91 3 . 4 . 513 .7 .O

10z

/.)1

3M

K :m :

40.8.29 17 2 0 85 0 2 4

9 T 5 3 14 1 0 813 .T .3 14

6 3 9 - 48.4.12.5t2 .6. I8.7

2 r 3 l16 .8 .24 .532.14.46.9

s ! 16 .7 .zT . rs : 5 2 7 9J : 5 2 7 3

ui r0.4.14.su i 3 1 4 51r 12.4.16.t l

H : 3 1 4 2 3 0 1s : 6 2 8 1 s I 3J : 7 . 2 . 9 . 1 1 9 2 0

G : 7 2 9 5 7 0 2e t 4 1 5 6 5 1 0z 16 .4 .24 . f i f i . t . 3

F :SR:

D i

A .b: '; :

A:B :

ql

[ ;

@:> :A .

:o .T :v

27J I

6

12

l3

I1 11

3I

19

l . )

I

51

1?-

7472

I1 1

J

4 1 5 3. 5 1 6 16 r 7 5

24.4.28.57 1 8 e14.2.16.s

8 . 1 . 9 . 1 032 .4 .86 .717 .2 . I 9 .$

9.r . '14.2s7 .4.41.361 0 . 1 . T T . 3

n.+.44.922 .2 .24 .s13 .1 . I I . 3

32.2.94.917 .1 . I 8 .46 7 '.13.20

2 3 8 * r 4 . 5 . 9 . 1 4 9 5 0240* s 16 20.36.5 19.3.T7243* t 9 .13.22.5 r2.3. -LA

A

5

a

97r1

3826

Irby{7

14J

2108

1977^

A

I

I1z

I J

8l . )

IJ

1

641

6 :i t :

q :F'f

I

rD

v

fpi

Bq:0 .

2M250*251

673?526*258

263264265

268270544+

549?2742764

277282283

285*287292

293296297

298299301

303304315

2 3 5 8 5 3 03 . 5 . 8 . 1 3 8 5 03 5 8 4 5 2 3

32.56.88.69 63.s1 .2532.s6.88.4s ss.23.3314.26.4A.n 25.1r.15

7 .11 .21 . r t 13 .6 .8s .10 .T5 .7 9 4 64 . 8 . T 2 . 5 7 s 5

2 4 6 1 3 1 35 . 1 1 . 1 6 . 6 9 4 717.38.55.24 32.r5.23

6 . A . 2 4 . 7 1 1 . 5 . 98 .20 .28 .9 15 . 7 .133 .8 .T r .4 6 3 5

12 .32 .44 .13 23 . r r . 21r 3 4 r 2 r 26 .20 .26 . r3 15 .9.1 1-

12.40.52.11 25.rc.-n2 7 9 4 s 3 41 4 5 3 3 2 2

8.32.44.2r 23.r5.T72 . 8 . m . 3 5 3 57.28.85.9 17.10. I8

4 . f t . 2A3 9 .5 .n3 .13 .1 -6 .8 9 6 74 .20 .24 .17 15 .11 .9

2 . r0 . I 2 .7 7 5 54.20.24.1L 13.9.172.13.15.4 7 s I

436.re.31 25.2r .151 . 1 1 . T 2 . 8 7 6 52 .9 .TT .s 6 4 5

The serial numbers used for each form in this table are taken from a recent paper bythe author, calcite, An Angle Tabre and critical List, privately published in May, 1943,by-the Dept. of Mineralogy and petrography of Harvard university as contribuiion No.259' A limited number of copies of this paper are available at publication cost, 50 cents.

Numbers from I to 328 indicate the certain formsl from 329 to 630 the probable anduncertain forms; 631 to 696 the discarded forms.* New forms.

319*322*300

irNird i lN i lNilN i lN

6 6 r : c n + o r N F 6+ o + - + N N e + e E

KN8 R \g 8EP BS

i lNilN\ o N \ o d r o l i

: 4 \ o r N rF r r t s 6 < r

: lF rid

o \ r r \ o c l \ o4 n n N < i

b € d N + r

l t t l l l

i lN i ln i lN i lN

+ + 4+ + 4 q e o 4 O O F < :N N d l o . o o e \ o o < ' + Di i N i H : : i N N N

sRR e$n Ses SS: sH"s qs$ HsS€ € € F S ; T T R F F t r f , F R K \ 3 P S g

e.Es $a= $sE o \ € : l : S Kr r t l t t l l

i lN i lNrli i lN

+ N r n N : o \ c o \ or 4 o o a n n ) * o o

C \ O O \ + + + ' ' 4 @ \ ON N N N N N

Bus 5BB \s$ KRg xs f r sss g3= 38 f i K%s gss\ r . p ! - \ \ q e i s s f i R r R F F F f , F R R K E q \ S € q Fr N N r @ + 6 C €: i ' i ' i

' i - i l Y Y T

- i l ' t ' - r - l - l ' - r I I I I I I I I I I L I

g :s : t * : s3 l : 3 383 $ ;8 S ;A g ;E tC : 5 \Ekps Fss e€€ F i lB rRF FFF ss * KFB R \s EEF

sxn 3s9 338 B :K K ts : F38 5e3 eR5 e :8 S i l :?" sqn ?;+ JSe NsK KK\ \ \T ITT :?? TTi- l i i I |

- l I I I I I I I I I I I I

O O \ O N + n o g O 9 O N Q \ L ? 9 9 q ! ' + O o r 4 9 4 : N e N O No d N N e < o + e + 6 ; ' ; 5 + e n o - * a q r - N t - t + N -

b * o . N N + o o o e \ o c o t A a 1 n 9 x i 9 - - & 4 v 5 & i + r: : c s i : J : - N N N N N N N N

N O \i N

.oEz

l* ^ .?rE :L^ -!3 r^.o qae i, lR =ri l ' : ; i l i l - , ; 5,:Sr=f Ems EE,i EieFi mSp FNrl Fd'r -r :F5 n&i6 |: ; r : E ;+ =e l *n{ i : i i " : : : : f * :s }Eq g l :? ; ' :g I : ; ; ; ss ; 3 :s $o ie eN: i ; : : :s ies : is : :

i lNild i lNrld i lN

$gx 9 :9 93 t \ 3R 9 f r3O \ O + \ O N O c O € 9 N N N + \ o q€ \ o \ o N 4 4 N N r r r r r r N

) o i d : N i r d\ O O \ r € i D : O @o i N e + r D N H S

O r O \ N N + O , * Oi i N

irN ilN i lo

F d o a O N O o Or + N A d a $ i $

4 4 \ o \ o r N o € sN N N N N

r t l l

D N € S O O4 O N 4 N < r\ o r N a € oN N

l l l l

<r +'

N N

ilN ild:rN^ r 6 - 6 Ns q + N Q

ECS 3 t

$ €

+ 6N < 4

o c o dO i No r o \

\ ilNilNN \ O - O N T

: D \ C N N TN r r N m +

N N

S N

N N

o

cdF

OF.l

(-)o

a

M

Fl

ts

Z

il

v

N

F.ltrFr

N r 4 O \ g t O O r O O \ S r N i e + O < r n D i r S € N \ O +

h E e o O + < t r + r \ O 4 e r: N O i

O N d r N n r O \ \ O \ O r S Q - : 1 < 'i O i N

6

d

cd(.)

3.{ '$ ' i 'L1;.. ,qt:E b'RN '{81' a5"na'

'c 'r . ' - ' e S ' *ElA' **Qcq 'aV

CALCITE FROM LAKE SUPERIOR COPPER MINES 39

utI6.16.32.9|-This dipyramid is well established by concordantmeasurements on a number of crystals. Its faces are of good qualityand often of large size. It is illustrated in Fig. 9 of the 1898 paper andin Figs. I and 2 of this paper. It has been reported at Lingban, Sweden,by Flink and Aminoff, and at French Creek, Pennsylvania, by Gordon.

j: {11 .7.18.4}-This scalenohedron of the principal zone is a minorform well established by the measurements shown in the table. It isnot f igured._

c : { 9 . 5 . 1 4 . 3 ] t , r i 1 3 2 . t 4 . 4 6 . 9 ] t , s j { 1 6 . 7 . 2 3 . r 1 , t : 1 3 7 . 4 . 4 I 3 6 1 . -These four new scalenohedrons were found on the crystal from theTamarack Mine shown in Figs. 3 and 4. This unique crystal was loanedfor study by the late Mr. Reeder of Houghton. It is a twin crystal ofperfect symmetry and superb quality, its greatest dimension aboutone inch. The twin and contact plane is (0112). The crystal was firstmeasured with one individual in a normal position, and this is figuredwith approximate fidelity in Fig. 3. Besides the familiar Lake Superiorforms, such as P., N, M., Ui, K: and IZ, there were found the new forms,developed in part as the largest and most brilliant faces on the crystal,each with two faces on each individual of the twin. gj and r! are par-ticularly well developed and despite their large size gave single signalson the goniometer of great brilliance. So surprising was the presence ofthese new forms that they were measured four times with repeated re-adjustment of the somewhat unwieldy crystal, but the measurementswere concordant. The table of angles shows that the forms give meanposition angles in reasonably good agreement with the calculated values.There are no zonal relations which aid materially in establishing theirsymbols. The form 128.16.4+.9| with phi 8'57'and rho 76"41|' is theknown form nearest to qi. However, this form is in a zone determinedby m. and U 1 , a zone in which the new form does not lie as may beseen in the drawing. rj is close to the form {7.3.10.2} found by Flinkat Lingban but apparently not as well substantiated by Flink's measure-ments as is r;. In the fig. K.'seems to symmetrically truncate the edgebetween ly' and qi but in reality it is not quite in the zone. lj is, on theother hand, in the zone determined by p. and ny',' but to make thesymbol, complicated at best, conform to this zone prevents one fromidentifying it with either of the known forms near it in angle, all ofwhich belong to the principal zone.

t : s7 .4 .4T .36A : 1 1 . 1 . 1 T . 1 0B : 17 .2 . ' 19 .15

1 0 . 1 . I I . 9

a24'55+'2s 4r+24 3025 t7

p

47001'48 4l49 56+49 06+

40 CHARLES PALACHE

The four forms are put forward as highly probable, although not estab-

Iished by this one observation.The crystal was also completely measured with the twin plane and

the two basal planes vertical. The result is shown in Fig. 4, which is an

orthographic projection normal to a face of {1120}. The figure is slighly

idealized and some of the minor planes are omitted. No other crystal

remotely like this one was seen among the many hundreds examined

during this s_tudy.b {20 . 11 .31 . 15 } , o {37 . 19 .56 .21 } -These two sca lenohed rons a re i n

a zone between K : l2l3l ] and zr' I ll2Jl . They are weak f orms but occu r

persistently, either together as shown on Fig. 6 (Palache, 1898) or each

by itself as in Figs. 7 and 24. In the zone with them, well shown in

nig. O, is another , more common Lake Super ior form, lo i 17 '4 .11 .61 ,f irst found by Irby and repeatedly in this study. M: 1I5.8.23'10]1,found by Whitlock (1927) on New Jersey crystals and once on a Lake

Superior crystal, is also in this zone'

M18.4.12.5] -This scalenohedron is an important member of the

Lake Superior form series. It is shown in minor development in Fig. 9(Palache, 1898). In Fig. 1 of this paper it is a major form and was seen

on many crystals, always of good quality and in good position. It has

been found also by Whitlock in New Jersey and by Gordon at French

Creek, Pennsylvania.Ut 110.4.14.3|-This is the most important of the new forms. ft

was measured on ten crystals and seen on twenty others, always with

faces of great perfection and in extremely accurate position. Its zonal

posi t ion between m. la}4 l ) and 7{8.S.16.3} helps to ident i fy i t , as m.

truncates it with parallel edges. It is shown in greater or less develop-

ment in Figs. 2, +, 5, 7 , and 14 (Palache, 1898), indicated by the letter [/

without dots; in this paper it is shown in Figs. 3, 5, and 6. It was new

in 1898 but has since been found at such widely separated localities as

New York State (Whitlock, 1910);Lingban (Aminofi, 1918);Terlingua,

Texas (Eakle,1907); Blaton, Belgium (Buttgenbach,1920); and Lions-

ville, New South Wales (Smith, 1927).It takes rank as one of the com-

mon forms of calcite.N1I2.4.16.11|-This is a strongly developed and rather common

scalenohedron in Lake Superior crystals. Seen on fourteen crystals andmeasured on six, it shows a notable stability of position. It was figured

on two combinations in 1898, Figs. 6 and 19. The relation of ny' to thegroup of negative scalenohedrons Di , C and Si which are described later,

is of special note. Iy' has a strong tendency to form with Di an oscillatorystriation made up of brilliant facets parallel to the two forms. This

stepped surface impinges upon C or Si , one of which forms is almost

CALCITE FROM LAKE SL]PERIOR COPPER MINES 4I

invariably present, in an irregular zig-za"g intersection which cannot beaccurately shown in a formal crystal drawing. Figure 7 is an attempt toshow this relation, but the steps of the striation surface are too broadand too few to bring out the characteristic irregularity of the intersectionwith C. The relation is fould repeatedly, often on large crystals of mag-nificent brilliancy and clearness. The zone N-bi contains a pole of0.10221 ] and one oI Z,next to be described. 1[ and Z also form a simplezone with p. which contains 17.4.11.6|, mentioned in a previous para-graph, and the important form {4.4.8.3}. These zonal relations estab-Iish the importance of this new form, which has not as yet been foundelsewhere.

2116.4.20.15)-This scalenohedron was seen on as many as th i r teencrystals but was measurable on only three. Its typical occurrence is oncrystals of negative scalenohedral habit with narrow triangular facetsas shown in Fig. 17 (Palache, 1898). But on Fig. 15 of the same platethe form ly' is shown with a similar appearance, and measurement isnecessary to distinguish them. It is also shown with ff in Fig. 6, and itszonal relation to that form has already been described.

The series of eight positive scalenohedrons beginning in Table 2 withthe fo rm L i { 32 .4 .36 .7 } and end ing w i th I i { 17 .1 .18 .4 } we re a l lreported in 1898, with the exception of the only doubtful one, O!. Theyform an interesting and very complex zone series lying on both sidesof {4041} in the direction of a face of the prism ltIz}l. Included withthem in the zone are the much more important and common forms114.2.16.31, [5161] , and {6281}, a l l o f which, as shown in Table 1, are

frequently occurring Lake Superior forms. The varied developments ofthis series on crystals of a variety of habits produce one of the mostcharacteristic features of the calcite of this region. As may be seen fromthe angle table, thev lie very near to each other, and therefore tend toproduce a more or less striated surface when several are present. Eventhen, however, the signals from them are distinct, and each one of themhas been observed at least once without another of the series. With theexception noted they are regarded as well established although but oneof them, iDj has as yet been found elsewhere. The series is shown in fulldevelopment in Fig. 2 (Palache, 1898) and less fully developed in Figs.5,7, 14, and 19. Figures 3 and 5 of this paper also show some of theseforms. g: {32.2.34.9} is shown in F ig. 5. I ts posi t ion is good, but i t isdoubtful because not seen except on this one crystal.

y l O . 7 . I 3 . 2 0 } , * { 4 . 5 . 0 . 1 4 1 , a n d , u : { 3 . S . 8 . 1 3 } - T h e s e t h r e e n e g a -tive scalenohedrons belong to that part of the crowded terminal principalzone of ca lc i te Iy ing between {0112} and 11123}. The f i rs t two werefound on several crystals of one specimen. The faces were distinct,

l n CHARLES PALACHE

present on each crystal in full number, and show little variation of posi-

tion. They are shown in Fig. 8 in typical development. The third form'

!'t,:, was reported in 1898 and has a wider distribution, having been

measured on four crystals and identified on several others. It is shown

in Figs. 13 and 23 (Palache, 1898), in the latter truncating the edge

between the base and Di {3.5.8.4} . A l l three may be regarded as weak

but well-established forms.s [16 .20 .36 .5 ] , , { 9 .8 .2 t . 5 } -These two fo rms were found on the

five measured crystals taken from a group from the Allouez Mine and

were seen to be present on every crystal. They are generally small facets

but in a few crystals are more largely developed. The reflections obtained

from them were very good and the position angles show little variation,

so the forms may be deemed established. They are shown in Fig. 6'

Their zonal relations are not marked.Probably more than half of the calcite crystals from Lake Superior

Mines are dominated by negative scalenohedrons. This feature was

stressed in the earlier report and many figures illustrate it. Figure 9 is

introduced here to show the character of the simplest of these negative

formsrrhen symmetrically developed. The two forms 6i [3.5.8.4] andp: {1341} compose it and give character to many of the crystals.

These two are also the most common negative scalenohedrons to be

found on calcite the world over, but elsewhere they generally occur as

minor modifying forms.

{1341} is a peculiarly stable form, faces measured on different crystals

rarely varying more than a few minutes from the calculated position.

This is not true of {3594}, however; when crystals bearing this form are

measured, it is found that the position angles are variable through a

considerable range of angle and often the faces are faceted and yield

two or more sets of position angles. In other words, a vicinal develop-

ment is common. In the following table are brought together the various

forms found in the literature of calcite that group themselves about bi

b: 3584 523 -8"1d3' sqfss' commonS: 32.56.88.45 55.23.33 -8 57 59 24+ NewC 14.26.4A.21 25.11.15 -9 4e+ s8 48+ I rby (1)

29.fl.8A.4r 50.21.30 -s 0+ s9 2r+ Irby (2)6. r r .17.9 s2.14.19 -9 38+ s8 34+ I rby (3)56.98.15;I.81 -8 57 58 41+ Ifessenberg (calculation in error due

29.53.82.43 154.6\7.92 -9 35to false zone)

58 49 Cesiro (1891)

After studying the measurements of scores of crystals it was finally

concluded that the existence of two vicinals to D! must be recognized:

C, established by Irby after remeasurement of a crystal of Hessenberg,

CALCITE FROM LAKE SUPEKIOR COPPER MINES 43

on which he had determined the very complex symbol of the table;s; corresponding to a set of angles found even more frequently thanthose related to c. Each of these forms may occur alone on a crystal,along with either of the others or with both. There is nothing to choosebetween the quality of reflections obtained from all three. of the otherfour forms in the table, frby (2) may be merged with S: ; Irby (3),Hessenberg and cesdro with c. ces)ro's symbor was the result of anelaborate calculation of the measurements of a single Lake superiorcrystal which chanced to be dominated by the vicinal form c. The choiceof the particular symbols of c and sj was in part fixed by the conditionthat they both l ie in the zone determined by 6; and X., a rather commonrhombohedron. This zone also contains two forms sti l l to be mentioned,c and b .

6i determines with {1341} a dominant zone on at least harf of thecrystals studied. In this zone lie the following forms:

3 ; (4 . 8 . 12. 5) one of the most common neaative scalenohedrons.F (5.11.16.6) Schnorr, 1896. palache 1898 as new. Establ ished.A (6.M.n.7) Palache, 1898. A weak form seen but twice.J (8.20.28.9) Pirsson, 1891. See below.I (7 .17 .24.8) Palache, 1898. Now unired with T.y (12.32.44.13) vom Rath, 1877. See belorv.B (12 .40 .52.11) Palache, 1898. A weak form but established.

Concerning the forms f and. IZ there is much the same story to betold as about D; ; each is the center of a group of poorly established f orms.

, b pJ 8.20.n.9 15.7.13 -73"54, 69"56, pirsson, 1891I 7 .17 .24 .8 13 .6 .T I _13 J l+ 69 13+ pa lache, 1898

25.64.94.32 49.24.TI -14 23i- 68 0Z+ Dana, 1873, no angtes9.23.32.10 17.S.1-d -14 10+ 70 2S+ Gonnard, 1897

The form -/ was found by Pirsson on a crystal supposed to have comefrom Guanajuato, Mexico. rt gave good measurements and was in thezone defined above. Had this form been known to the writer in 1g9g,the form 1, which is very near to it, would not have been proposed andis now withdrawn. Gonnard's form from Couzon, France, gave measure-ments which are almost as close to the angles of pirsson's form as tothe more complex one proposed.

6 o

CHARLES PALACHE

Frc. 1. Calcite showing the forms; o {0001}, a {16.16.32.91,1' [10T1]' z '{0554},{ '

{0443}, p. lo332l, M {8.4.12.5},q: [2461], Sr {32.56.88.45}.Frc.2. Calcite showing the forms; o {0001}, o [16.16.32.9], p. [1011], m' l404l l ,

I. 108871, K: l2r3rl,C U4.26.m.2r]r,p: {1341}.

CALCITE FROM LAKE SUPERIOR COPPER MINES 45

These various symbols show that z is in a disturbed region similarto D! . The form last listed is maintained by vendl after extensive dis-

falls into the important zone under discussion.1. { 17.38. 55.24] ' , D{3.S.TT.4}-These two scalenohedrons form wi th

l0ll2l a zorte which very nearly, but not quite, contains C. 1. bears tothe strong form {4.8.12.5} the same relation that c bears to D: thatis of a vicinal to its simpler, stronger Iorm. D is arso near to,4, but it isa more defi.nite form and was recognized on ten crystals. I. and, D arcshown in Figs. 10 and 11, and their zonal relations are best seen ingnomonic projection (Palache, 1898).

c{a.2o.24.171, b14.36.40.sf } -The f i rs t o f these forms was re-

Frc' 5. calcite, Lake superior. one coign of a crystal showing the forms: u ltr2rl,p.-lr01rl, n. l4o4rl, K: l2r3r.l, H: l3r42l, u: 00.4.14.31, tri isrorl, ̂ i t32.436.71,o: {e.1.m.2},r: 110.1.TT.3}, oi 11tr..+.a.oi,'ai'1iz.z.w.oy,'1,'isis+i, s: isi;.88.+sl.Shows also a basal twin lamella.

Frc.6. Calcite,Allouez Mine, Lake Superior, shorving the forms: a ll12}l, a {44g3},m, l4o!, r. {0881}, P: l321rl, M 18.4.T2.s1, U: {10.4.t4.3}, S: t62Bi}, , 1io.zo.ae.sy,t l9:8.n.51, C .14.26.m.2t]1, J l8.ZO.n.%, e: |i7.28,86.9|. Drawn'Uy nowrrd T. Euunr,Jr.

CHARLES PALACHE

CALCITE FROM LAKE SUPERIOR COPPER MINES

The crystal of Fig. 13 (Palache, 1898) shows it, and it was found withgood faces on the crystal shown here as Fig. 10. This form is well es-tablished.

Two figures have been added to this paper to show unusual habits forLake Superior crystals. Figure 11 is remarkable for the large develop-ment of the pr ism/{10.1.11.0} , which is found f requent ly but is gen-erally very subordinate. It was reported as new in 1898 but was foundlater to have been described elsewhere. Figure 12 shows what is veryrare in the whole Lake Superior region, a simple rhombohedral type.However, the f orm is a rare one {0. 13. 13. 1 l .

The paper to which constant reference has been made is "The Crystal-Iization of the Calcite from the Copper Mines of Lake Superior," byCharles Palache, Geological Suraey of Michigan, Vol. VI, Pt. II-Ap-pendix, pp. 161-184, Plates II-16, with 24 figures and a gnomonic pro-jection. It will be noticed by any reader who refers to the 1898 paperthat the Goldschmidt Gg and the Naumann crystallographic symbolsthere used have been discarded. This is in accordance with recent usagein this laboratory. The Bravais symbols used here are given in the olderform list along with the others. The letters used for the forms are thesame.

The review of the early study has shown the need of the followingchanges:

A form Pl l3 .7.2O.3l was descr ibed on page 176 of that paper andil lustrated as a tiny facet in Fig. 7. As this form was not found again,the crystal was remeasured and no measurable face was found at theplace indicated. The form is, therefore, withdrawn as based on an in-explicable error.

Frc.7. Calcite,LakeSuperior,showingtheforms:p. [10T1], m.l4}4l l , I f {12.4.m.11},Ei 114.2.16.31,b: {3584}, C

.14.26.N.21\,p: {1341 l . Trvinlamellaeparal lelto {01T2} are

indicated.Frc.8. Calcite, Lake Superior, showing the forms: 2. {10T1}, m. l4}4l l ,6. {0112},

/ . {0554}, E.1044-7},0.[O22rl ,y [7.6.13.20\,r {4.5.9.14}, C l I+.26.4.2rJ,8: {5.10.15.7},r [3 .13 .16 .8 ] .

Frc.9. Calcite, Lake Superior. Illustrating the commonest type of habit in the region.The forms are o {0001 }, p. ll0Tl\, m. 14041\, b: {3584}, and pi { 1341 }.

Frc. 10. Calcite from Champion Mine, Lake Superior, showing the forms: r'. [ 1011 ],m. [40411,6 . 10112] , 6 . to2zr l , l : [32571, K : l2 l3 r ] ,6 : [7 .3 .m.4 ] , and K {1 .11 .12 .8} .Drawn by Howard T. Evans, Jr.

Frc. 11. Calcite from Lake Superior. Unusual habit showing as dominant the prism.r {10.1.TI.0}, with 4. [0221], rr. 10881], y: 123581, a: [3.5.8.13], and Q: [19.13.32.6].

Frc. 12. Calcite, Lake Superior. Very unusual habit for the region showing chiefly therhombohedron C. t0.13.nt.1], an uncommon form on calcite, with 6. l022ll.

47

48 CHARLES PALACHE

Figure 11 o f the repor t shows a fo rm le t te r S : {2 .9 .11 .5} . Th is fo rm

was by an oversight omitted from the list of forms.

The form f '121.35.56.44} was l isted in the report and shown in Fig. 5,

where i t truncates the edge between {0001} and 6! {3584}. I t was after-

wards found that that part of Di which meets the base was actual ly Si

and tha t E was in the zone be tween the base and {32 .56 .88 .45} . To

meet this condition the symbol of E had to be changed and took the

form {32 .56 .88 .69} . Th is subs t i tu t ion was repor ted by Whi t lock (1910)

in his list of calcite forms. The form was not seen again and is regarded

as extremely doubtful.

RsrBnnNcns

Aurxorl (1918), Geol. Fdr. Fdrh., 40,273.BurrcaNsecu (1920), Soc. Jr. Min., Bull. 43r 24.CosAno (1891), Sac. geol BeIg. Ann.,18,63.Earr.n (1907), Dept. Geol. Unia, ColiJ., Bul,l.5,91.Fr.rNr< (1914), Ark. Kem. Min.,5, l.FruNznNru elto VnNnr, (I93O), Mat. Term. I,ud. Ertes, Builapest,47, LGoNN,*o (1897), Soc. Jr. Mi,n., Bul,l,.2O, 18.Gonoox (1928), FestschriJt V. Gold.schmidt, Pt. 11, 108.Gnrr,r. (1912), P ubl. I st. S tuili sup. Fir enzi, Abs. Zeit s. I{ ri st., 55, 387 .HnsseNsnnc (187O), Senckenb. Natur. Gesel,l. Abh.,No.7.Innv (1878), Inaug. Di.ss., Gcittingen.Prr,rcnn (1898), Geol. Sura. Mich., VI, Pt. Il-Appendix, pp. 161-184, Plates 11-16.PrnssoN (1891), Am. four. Sci.,4l,6l.vou RAtu (1876), Pogg. Annol., 158, 414.SelqsoNr (1890), Gior. il. Min., l, 129 .ScrrNotn (1896), Abs. Zei.ts. Krist.,30, 160.Sn:r,r,e (1856), Roy. Acc. Sc. Torino,II Ser., 17, 289.Surrn (1927), Atrstrali.an Mus. Rec.,15, 313.Vruor. (1921), Fiildt. Kiisl..,50, 131.Wnrrrrocr (1910), New York State Museum, Mem.13.- (1927), Am. Mus. Nat. Hist.,8u1tr.56,351.