Friday, 14 June 2013

An Article on Gemstones

A GEMOLOGISTS PERSPECTIVE



SYNTHETICS AND SIMULANTS

-Raunak Agarwal
Gemology Instructor, SDI


Synthetic Gems
SYNTHETIC GEMSTONES
Synthetic means "put together". A synthetic(or laboratory- grown) gem is made from the same raw materials as the natural gem.

It is optically and chemically identical to the natural gem, but it came from a lab.

 The drive for synthetic began when industrial diamonds were needed during World War II. It took years to develop industrial- grade diamonds, and years more to be able to manufacture stones of gem quality. Producing the early   gem- quality diamonds was more expensive than mining for natural diamonds. Improved technology brought down the price of synthetic diamonds.

 When a gem made of non- natural material is offered for sale, it is the seller's responsibility to inform the buyer that it is not a natural gemstone. This disclosure must be made at all levels of jewellery sales. Synthetic gems cost only a fraction of the price of natural gems.


SIMULANTS
Simulants 

Simulants are imitation gems, fabricated from such materials as glass, ceramic or plastic.  resemble the appearance of the gem it is mimicking, but it cannot duplicate the true gem's characteristic properties. Simulants have different physical and chemical properties. Some common simulants of diamonds are synthetic moissanite, CZ(cubic zirconium), YAG(yttrium aluminum garnet) GGG(gadolinium gallium garnet), strontium titanate and synthetic rutile.
 A gemologist can easily distinguish a real gem from a simulant by using appropriate lab equipments.

Are Certificates Necessary? 

It is always a good idea to insist on a gemological certificate. The extra assurance of a gemological certificate not only provides peace of mind, but it can be useful for insurance purposes and future resale also.

For some coloured stones, treatments greatly affects the value of the gem. For example, an untreated ruby is worth far more than a treated one, an untreated sapphire is far more valuable than from an enhanced one.

(SDI) Solitaire Diamond Institute Gems & Jewellery Lab provides certification services also.

The lab report comes with shape, measurements, colour, clarity, R.I, S.G, weight and determination as to whether the stone is natural or synthetic. It may also indicate whether the gem has been subjected to treatments.  
SDI Lab Certificate

SDI Lab Certificate

Bibliography: 
Various Internet Sources