Jet of the Day 11/28/11 - The Silver Bear

  
What is a Gemologist?

Gemology is the scientific study of gemstones, so a gemologist is someone who has undertaken several year’s study & passed the requisite examinations of an organization such as the GIA (Gemological Institute of America) or one of its overseas equivalents e.g. the Gemmological Association of Great Britain, or Australia.




 A gemologist is the person who has the sad task of informing you that the beautiful “Ruby” in grandma’s ring that you have just inherited is, in fact, a Garnet or, worse still, glass.

A gemologist undertakes a minimum of two years intensive training into the scientific identification of precious, semi-precious and ornamental gem materials. This encompasses geology and mineralogy, in order to understand the occurrence and structure of the various stones. It covers physical and optical properties, and all the various enhancements, simulants and synthetics.

If one takes a piece of jewellery containing a gemstone in for an insurance valuation, the valuer or appraiser cannot assign a value to the item unless a gemologist has first identified the stone. As a gemology lecturer many years ago, I used to take to the first class of each year a suite of twelve 4mm round brilliant (diamond) cut colourless gemstones. To all intents & purposes twelve identical stones, but some appearing to have a bit more “sparkle” than others. These 12 stones were –
Quartz
Topaz
Strass
Danburite
Synthetic Spinel
Synthetic Corundum
YAG (Yttrium Aluminium Garnet)
Zircon
GGG (Gadolinium Gallium Garnet)
Cubic Zirconia
Strontium Titanate
Diamond
and of course now we have the latest diamond simulant – Moissanite.
The object of the exercise being to demonstrate to a class of new students what they were setting out to achieve – the ability to correctly identify each of the twelve stones.

It’s quite frightening to think that there are very few gemstones these days which cannot be produced in a laboratory. Even common and relatively inexpensive stones such as Amethyst (purple Quartz) are being synthesized.

The synthesizing and treatment of gemstones has been around for a very long time. Synthetic Ruby was being commercially produced by the Verneuil process in 1902. It is estimated that over 95% of the natural (earth mined) Sapphires on the market today have been heat treated to enhance their colour, and probably 70% of all Sapphires on the market have been produced synthetically. (A synthetic gemstone is one which is identical in all respects to its natural counterpart, but has been man made. A trained gemologist is able to tell the difference. A jeweller (if not a gemologist) isn’t.)

Apart from the various process for creating synthetic gems – hydrothermal, flux, fusion, Czochralski and skull melt, there are innumerable treatments, some of which are bleaching, coating, dyeing, filling, flux healing, heating, impregnation (stabilizing), irradiation, lasering, lattice diffusion, oiling and waxing.

Simulants are rife - a very high percentage of “turquoise” being sold on the internet is, in fact, dyed Howlite or Magnesite. A good 90% of the Malachite being sold on sites like eBay has been man made (& is usually not identified as such!) The list goes on and on.

A gemologist can do more than merely identify a stone. He (or she) can tell you if that red stone is a Ruby, or not. If it is, he can tell you whether it’s natural or synthetic. If synthetic, he can identify which of the several processes was used to manufacture it. If natural, he can usually identify the origin of the stone by its colour and/or inclusions. If treated, he can identify the treatment.

A gemological qualification is a virtual “must have” for anyone in the industry these days. This is your BASIC qualification. There are a number of post graduate courses available, such as the DDT (Diploma of Diamond Technology), Appraisals, Pearl Grading, Opal Grading and others.

If any JET team members ever have any questions of a gemological nature, I’m only a convo away. Anytime.

Thanks for reading.

Bearsie