SYNTEST F Horizontal Immersion Microscopy Made in Germany

SYN F Horizontal immersion microscope base for examination of coloured stones in immersion liquids of corresponding refractive index. The exclusive access to the “Internal World of Gemstones”.

The traditional European gem microscopy following the famous design of Prof. Schloßmacher, Idar-Oberstein.

Trinocular ZEISS StereoZOOM optical system totally magnifying 6.5x – 50x or Optical System 10x – 80x , max. 250x at SYNTEST horizontal microscope base, ready for DIGITAL photomicrography. Extension By a corresponding adaption ring, most StereoZOOM optical systems, used with Options vertical darkfield microscopes, can easily be mounted onto the SYNTEST base, for Vertical such as GIA’s BAUSCH & LOMB, AMERICAN OPTICAL, LEICA or OLYMPUS; MEIJI, Microscopes KYOWA, MOTIC and more. Light Source High intensity LED lamp for powerful 6,000 Kelvin daylight illumination: Choice of transmission, incident and darkfield mode of light. Illuminator rotatable around the gemstone for variation of light incidence. DIM Control for electronic dimming of light source. Stoneholder MAGNETIC CLICK stoneholder system with magnetic socket. & Mounting Possibility of mounting for right- as well as for lefthand use.

SYNTEST F Horizontal Immersion Microscopy Made in Germany

Immersion Two immersion cells of 45 x 45 x 45 mm ( 1.8” x 1.8” x 1.8” ) size Cells and with magnetic device for secure hold on stage. Liquids Immersion liquids of nD 1.57 and nD 1.66 each 100 ml Polarisation U-type polarization unit around the cell, both filters rotatable. Magnetic hold at cell holder. SYNTEST horizontal Microscope Base with Polarizer Unit, second Immersion Cell and Liquids. Stage shown for left hand use of stoneholder, but mountable for right hand use as well. Microscope Solid steel of rugged consistency. Resistant grey epoxy Base Design coating of distinguished elegance. Dimensions Base / case 330 x 185 x 95 mm (13” x 7 3/8 x 3 3/4”) Vertical max. height 300 mm (11 7/8”) Weight Base without optical system approx. 5,000 g (11.03 lbs) Power 220 – 240V / 50 – 60Hz 100 – 120V / 50 – 60Hz by optional voltage converter. Power cord 3-wire grounded, 1,800 mm (6'), adaptors for CH, IT and GB sockets . Degree/class of protection: IP 20/I Electromagnetic compatibility following the EU norms.

SYNTEST F Horizontal Immersion Microscopy Made in Germany

ZEISS trinocular StereoZOOM Optical System The high-quality ZEISS optical system provides an outstanding imaging quality Made in in terms of contrast and resolution. The trinocular system included in this Germany package is equipped with 16x eyepieces for a total ZOOM magnification of 10x - 80x next to the 10x ones magnifying 6.5x – 50x.

Outstanding optics design • apochromatic corrected ZOOM optics of ZEISS manufacturing • sharp, distortion-free 3D image over the whole visual field • mechanical corrected ZOOM curve for largest ZOOM range 8 : 1 • sharp 3D image in each ZOOM position • distortion-free 10x and 16x eyepieces

• wide field of view 25 mm at 10x • individual diopter correction at each eyepiece • eyepiece adjustment 55-75mm • c-mount adapter 0.5x • working distance 92mm

Digital Adapter

Digital camera as per customer’s choice

Adapter ring for connection of specific camera

Optical adapter to microscope

C-mount adapter

SYNTEST F Horizontal Immersion Microscopy Made in Germany

ZEISS Stereo ZOOM- optics binocular

SYNTEST F Horizontal Immersion Microscopy Made in Germany

SYNTEST F StereoZOOM Features Table for ZEISS Optical Systems

Features ZEISS 508

Optical System

Objective ZOOM Range 1) 0.65x - 5x Eyepieces 10x / 16x / 25x

Total Magnifications 1) with: Eyepieces 10x 6.5x - 50x Eyepieces 16x 10x - 80x Eyepieces 20x ./. Eyepieces 25x 16x –125x Field at 10x magnification with 10x Eyepieces (mm) 2) 23 Field at 10x magnification with 16x Eyepieces (mm) 2) 25 Eyepiece Distances (mm) 55-75 Eyepiece Diopter Adjustment both Working Distance (mm) 92 Optional front lenses 0.63x / 1.6x / 2.0x 1) (16x eyepieces) x (0.63x – 4.0x objectives) = 10x – 64x. In Gemmology the figure of 10x of the total

microscope magnification is used for diamond grading. Therefore most optical systems are equipped with 16x eyepieces. It’s a simple intention if starting with 10x total magnification to get a higher magnification at the end of typical 64x (instead of 6.3x – 40x with 10x eyepieces).

2) The field at 10x total magnification is the diameter in mm of the microscope picture viewed by the observer. It’s a quality feature of the eyepieces and the objectives. Typical range is 20 – 25 mm at 10x depending on the manufacturer of the optical systems. Of course, at 6.3x the field is much wider, e.g. 36 mm and consequently much smaller at 64x of only 4 mm.

3) Figures shown are without any front lenses!

EICKHORST & Co. KG Borsteler Chaussee 85– 99 · 22453 Hamburg, Germany T. +49 (0) 40-51 40 00-16 · F. +49 (0) 40-51 40 00-30 · info@eickhorst.com · www.eickhorst.com

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How to reduce the surface Reflections from a gemstone

EICKHORST & Co. KG - Borsteler Chausse 85-99 - 22453 Hamburg / Germany Tel: +49-40-514-000-0 – Fax: +49-40-514-000-30 - info@eickhorst.com - www.eickhorst.com

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In a previous issue I mentioned in this column how the inclusions in a gemstone can be used as an aid to identifying the stone. One of the difficulties in viewing the interior of a gemstone with a microscope is caused by light rays reflected back from the stone’s facets. A way to reduce these reflections is to inject the illuminating light into the side of the gem, so that any inclusions are highlighted against the dark background of the stone (on a suitably equipped microscope, this takes the form of darkfield illumination). An even better method, which both reduces surface reflections and helps to illuminate the interior of the gem, consists of immersing it in a liquid having a refractive index close to that of the stone (e.g. for emeralds, bromoform with an R.I. of 1.59, or for rubies and sapphires, methylene iodide with an R. I. of 1.74). The surface reflections are reduced in this case because the reflectivity of a polished surface is related directly to the refractive indices of both the surface material and its surrounding medium (normally air). This relationship is shown in the simplified Fresnel formula, Reflectivity = (R.I. of gem – A)² ÷ (R.I: of gem + A)², where A is the reflectivity of the surrounding medium (which, for air, is 1.0). For a ruby, the reflectivity of its surface facets in air is as high as 8% (it’s 17% for diamond), but immersing a ruby in methylene iodide reduces this to a mere 0.002%. Even water, with an R.I. of 1.33 will reduce the surface reflectivity of a ruby to 2%. When using the immersion technique to view gemstone inclusions with a microscope it’s convenient to mount the gem in stone tongs so that it can be orientated for all-round inspection. Unfortunately, with the standard microscope it’s necessary to use a shallow immersion cell so the stone tongs can be kept at a reasonably shallow angle to avoid masking the view of the gem. One way out of this difficulty is to mount the microscope head so that the objective lens views the gem in a horizontal rather than vertical direction. This then allows the stone tongs to be positioned vertically, and the gem to be immersed and rotated in a deep cell. Horizontal-objective microscopes of this type have been manufactured and promoted mainly by the German gemmological instrument company System Eickhorst. To minimize the expense of purchasing a complete horizontal-type microscope, System Eickhorst has

introduced a new “Horizontal Immersion Base “SYNTEST”. The stand is fitted with a circular clamp which enables it to be used with the head from an existing microscope (provided that this is removable and has an appropriate body diameter). The stand is fitted with a light source that can be pivoted to give incident, darkfield or lightfield illumination. Alternatively, the base can be provided with a choice of stereo heads, with fixed magnifications of 10x and 30x, zoom models with a range of 7x to 60x and a ZEISS trinocular zoom model (for camera attachment) with a ZOOM range of 6.5x to 80x. The overall magnifications of all these models can be doubled by fitting 20x eyepieces. For the zoom heads, the magnification can be doubled again by means of an objective-lens adaptor of 2x. For anyone who hasn’t already got a microscope, System Eickhorst also markets a vertical “Diamond Darkfield Stand”. This can be used with the same heads as the horizontal stand and is fitted with an innovative darkfield. By Peter Read, FGA published in “Canadian Jeweller”

The principle of immersion microscopy illustrated.