Throughout history gems have fascinated and been coveted by human society, but just what makes a gem? A gem must be beautiful, rare and durable. A new factor becoming more apparent, especially in the eyes of such associations as Gem-A is acceptability. Any material that meets these criteria can be a gem whether it is a faceted diamond or even carved green plastic imitating jade.
Broadly speaking there are two general categories of gem material, these are the traditional gemstones
such as a finished sapphire used in jewellery and secondly those classed as ornamentals,
such as a turquoise carving. A further subgroup is organics, which includes gems like pearls, amber etc. Gems are also often simply split into diamonds and coloured stones.
There are a few misnomers in use within the general public to do with gemmology and these can lead to confusion. The first is the most common, someone might ask “Is this a real gemstone or is it a fake?” A question like this can lead to troubling circumstances, a synthetic sapphire is 100% chemically and physically a real sapphire, but it was made in a laboratory by a man/machine. So is it a real sapphire? Yes. Is it also a fake? Some may also say "Yes". In this instance the term synthetic of laboratory created should be used. It is because of situations like this that gemmologists tend to avoid this terminology.
The second point is partially a matter of disclosure; the term natural is often used misleadingly. For example, you can have a natural ruby mined from the earth; however it may have been heat treated with lead glass to drastically enhance its appearance. It is the opinion of the author that it is perfectly acceptable to label gemstones as natural as long as any treatments (trade acceptable or not) should always be disclosed.
Lastly for years many gems have been classified as either precious or semi-precious, with the growth of gemmology and gemstone trade this terminology has become less and less relevant. Take two red stones for example, we sell low grade ruby rough stones for as little as $0.14 per carat and yet we also sell good quality spinel for $550 per carat and if you ask the average person on the street if they would like a ruby or a spinel you would not get many takers for the spinel.
It is important to come to grips with the general terms used in gemmology so each of these articles will be followed up by a mini glossary, so stay tuned for this weeks terms in the next couple of days.
So where do gems come from? The earth may seem relatively stable to us but on a geological scale it is a highly dynamic environment. It is these earth processes that give rise to the creation of gemstones. A quartz crystal may form from super-heated liquid that travels through cracks in rocks and begins to cool, the crystals may be mined from the rock or may continue to be processed by the earth to be deposited in a river to form what is called a placer deposit. Gemstones are still forming today just waiting to be brought to the surface.
Not only this but we can take the raw components of gemstones from the earth, refine them and then use them to create synthetic and imitation versions of natural gemstones. Lastly there are the organic gemstones mentioned above which are sourced from current biological life in the case of pearls and ivory or from ancient sources such as amber and jet.
In our next article we will take a closer look at some of the geology and mineralogy of gemstones.
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