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Refractometer Ref: refract

This is THE standard tester for gem testing. It is optical (not electronic), you see a shadow on a scale, read the number, then look it up on standard charts. Can be used with any gemstone that has a flat polished surface, whether loose or set in jewellery (click MORE to see a picture of testing a mounted stone). Note: will not test for diamond.

Supplied in a sturdy box (easily portable) complete with a bottle of refractometer fluid.

Instructions are NOT included with this item, it is assumed that you are either a gemmologist (or a student) or that you will be using a book about gemmology.

 



Price:    £211.91 / $328.46
 £248.99 / $385.93 Including  VAT at 17.5%

You will not be charged VAT if the order is posted to an address outside the European Union

Refractometer

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Electronic Gem tester by Presidium Ref: GEMTEST-PRES

Electronic Gem Tester by Presidium (includes diamond). Tests for ten groups of gemstones, though the readings do overlap considerably, click MORE to see.

This is a precision instrument and, unlike the diamond-only testers, is extremely sensitive and must be treated as a fragile laboratory instrument - it must be kept clean and dry and must not be bumped or abused. As such it is unsuitable for use by many antiques dealers and scrap merchants.

 
Detailed picture of scale


Price:    £169.00 / $261.95
 £198.58 / $307.80 Including  VAT at 17.5%

You will not be charged VAT if the order is posted to an address outside the European Union

Electronic Gem tester by Presidium

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Chelsea Filter Ref: CHFILT

Many stones appear to change colour when viewed through the filter. Originally designed for detecting synthetic emeralds, nowadays the Chelsea filter is an invaluable aid to identifying many other gemstones.

To read the instructions manual click here and decide for yourself if this is the most valuable tester a dealer could have...or far too complicated to understand!

 


Price:    £20.00 / $31.00
 £23.50 / $36.43 Including  VAT at 17.5%

You will not be charged VAT if the order is posted to an address outside the European Union

Chelsea Filter

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Polariscope Ref: POLARIS

The Item: A tube 80mm tall X 30mm dia.

What it detects: double refraction.

How to use: At the top and bottom of the tube are two filters (Polaroid discs), revolve the top filter until everything in the tube appears dark and place the stone on the platform in the middle (if mounted, you might have to fix the item upright with a spot of blu-tac so that you can see the stone). Now turn the platform so that the stone revolves through 360°.

What you see: If the stone appears to turn light-and-dark it is doubly refractive, if it remains dark it is singly refractive.

For the gemmologist: all crystalline gemstones except for those of the Cubic System are doubly refractive.

For the non-gemmolgist: Moissanite is strongly doubly refractive, diamond is singly refractive. This is, therefore, a very simple and effective method of distinguishing diamond from Moissanite. Instructions: not included. 


Price:    £23.40 / $36.27
 £27.50 / $42.63 Including  VAT at 17.5%

You will not be charged VAT if the order is posted to an address outside the European Union

Polariscope

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Spectroscope Ref: SPECTRA

The Item: a tube 50mm long X 12mm dia.

What is detects: absorption spectra. How to use: view the colour of a gemstone, either by shining a light (pen-torch) through the stone into the spectroscope if the stone is transparent, or by viewing its reflected light if the stone is opaque.

What you see: a spectrum (rainbow) which might be interrupted with black or white lines, it is the pattern of these lines you must learn to recognise.

For the gemmologist: best at detecting iron and chromium.

For the non-gemmolgist: the 'diamond simulants' YAG and Cubic Zirconia give spectacular spectra and so too does some Zircon. Other gemstones are more difficult to detect.

Instructions are NOT included with this item, it is assumed that you are either a gemmologist (or a student) or that you will be using a book about gemmology...see optional extra. 


Price:    £29.79 / $46.17
 £35.00 / $54.25 Including  VAT at 17.5%

You will not be charged VAT if the order is posted to an address outside the European Union

Spectroscope

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Add book, A Student's Guide to Spectroscopy