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Polariscope, handheld, with built-in light

Polariscope, handheld, with built-in light

Ref: POLARIS-L


Price: 37.50 Including VAT

Quantity:  

OPTIONS:

Gem ID Book £25.00 instead of £29.50 £25.00

Gemstones book £15.00 £15.00

{Summary}
A tube 90mm tall X 35m diameter, it detects double refraction.

Most gemstones are crystalline in structure. Some crystal structures are doubly refractive and some are singly refractive. Diamond is a crystal of the cubic system, it is singly refractive. Most diamond simulants (look-alikes, not diamond) are doubly refractive, including Moissanite.

So you could use this as an inexpensive tester to distinguish diamond from Moissanite. You cannot, however, use it in place of a diamond tester because Cubic Zirconia (another diamond look-alike) is cubic, just like diamond.

Included: soft carry-case, built in light (takes two 2032 batteries, included)

{Is it easy to use?}
Reasonably easy. 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. Now turn the stone so that it revolves through 360°. If it appears to turn light-and-dark it is doubly refractive, if it remains dark it is singly refractive. Read all about it in a good gemmology book (see Further Information), this item is not supplied with instructions.

Included: soft carry-pouch, light is built in (takes two 2032 batteries)

{Limitations}
The stone needs to be rotated on the platform. That's very easy with loose stones, but there isn't much room to fit stones mounted in jewellery, it has to fit onto the platform which is 12mm diameter.

Light must be able to pass through the stone, not a problem with transparent stones, you'll have to use a torch to shine light through semi-transparent stones, you cannot test opaque stones.

{Further information}

This instrument will show you if a gemstone is singlly or doubly refractive. For instance, Moissanite is strongly doubly refractive, diamond is singly refractive. This is, therefore, a very cheap (if a little fiddly) method of distinguishing diamond from Moissanite. At a more advanced level: glass and plastics are singly refractive, crystaline gemstones are mostly doubly refrective, excluding the cubic system of crystals (which includes diamond and cubic zirconia). So knowing if a gemstone is singly or doubly refractive is diagnostic.

This is a standard gem tester used by gemmologists, it does not come with instructions, you are expected to know how to use it (a bit like a bicycle, it does not come with instructions telling you how to ride it).

If you are new to gemmology I strongly recommend the book Gem Identification Made Easy. This book systematically works its way through all the optical testers, telling you the theory behind them, what they will test, and how to use them. To get your discount (£25.00 instead of £29.50) tick "Add the Gem ID book" when you order the polariscope.
{Extras}

Here are more details of the optional extras you can add to this order:

Gem Identification Made Easy £25.00 instead of £29.50 if you tick 'Add the Gem ID book' when you buy the polariscope.

Not as detailed, but good guide to gemstones, beautifully illustrated, is Gemstones.