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International Gemmological Institute (IGI)

BGI Building, 9 Soi Charoen Krung, 36 New Road, Bangkok 10500
Tel.: +66-2-630.67.26, Fax: +66-2-630.67.28
Email:thailand@igiworldwide.com

Ukraine
The State Gemmological Centre of Ukraine undertakes research as well as development and implementation of educational programs for training of gemmologists.

United Kingdom

The UK has well-organized gems and jewellery training facilities.
The Gemmological Association of Great Britain organizes training, the ambit of which now extends to overseas centres too. It is affiliated to the Gemmological Association of Australia, Canada, Zimbabwe and Hong Kong. Its FGA Diploma is

Gems Miscellany
Know more about gemstones to understand their nature, value and preservation for a long time. To help you, interesting and useful basic facts and figures pertaining to the miscellaneous physical, visual, technical, astrological and other aspects of various gems as well as their measured quantity, sizing and upkeep is being presented in this
appendix.

Moh's Scale of Hardness:

Developed by Moh, a German mineralogist, this table is not a scale in which the numbers indicate equal divisions of hardness. In other words, the intervals of hardness

Gem Weights
Carat:
This weight is used in the gems trade since ancient times. The name is derived from the seed (kuara) of the African Coral tree or from the kernel (Greek-kertion) of the Carob bean. Since 1907, Europe as well as America, have adopted the metric carat of 200 mg. or 0.2g. Therefore weights given for famous old diamonds often vary because local carats and not metric carats were used. The carat is subdivided into fraction (1/10 ct) or decimals (1.25ct) up to two decimal places. Small diamonds are weighed in "points" = 1/100 cts. (=0.01 cts.). The table below illustrates diametre and correspond­ing carat weight for diamonds cut in the modern brilliant cut. Gems with different spe­cific gravities and different cuts obviously have different dimensions. Wholesale labrorite Jewellery

Karat:
The carat weight of gems is not to be confused with the karat used by goldsmiths. In the case of gold, the karat is not a weight measure, but indicates purity of gold. The higher the karatage, the higher the content of gold in the assessed piece of jewellery.

Gram:
Weight used in gems trade for lesser gemstones and for rough gemstones(for
instance, quartz).

Grain:
(Latin - granum) Weight measure for pearls. Corresponds to 0.05 grams = 0.25 or
1/4 carat. Increasingly superceded by carat weights, the old Japanese weight- the Momme (=3.75 grams =18.75 carats) is hardly used any more in Europe.