Gemmology World Quiz
Gemmology World Quiz
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AMETHYST - a transparent purple variety of quartz,is one of the most popular of colour gems. The birthstone of February, it was once believed to prevent the wearer from getting drunk, and if the circle of the sun or moon was engraved thereon, it was believed to prevent death from poison. Available in shades from light to dark purple, it is relatively hard, fairly brilliant, and overall a good, versatile, wearable stone, available in good supply even in very large sizes (although large sizes with deep colour are now becoming scarce). Amethyst is probably one of the most beautiful stones available at a moderate price, although one must be careful because "fine" amethyst is being produced synthetically today. It frequently exhibits colour zoning (often looking like chevrons). Amethyst may fade from heat and strong sunshine. 
AQUAMARINE- a universal symbol of youth, hope, and health, blesses those born in March. (Prior to the fifteenth century it was thought to be the birth stone for those born in October.) Aquamarine is a member of the important beryl family, which includes emerald, but aquamarine is less brittle and more durable than emerald. Aquamarine ranges in colour from light blue to bluish green to deep blue, which is the most valuable and desirable colour. It is a very wearable gem, clear and brilliant, and, unlike emerald, is available with excellent clarity even in very large sizes, although these are becoming scarce today. One must be careful not to mistake blue topaz for aquamarine. While topaz is an equally beautiful gem, it is usually much less ex pensive since it is usually treated to obtain its desirable colour. For those who can't afford an aquamarine, however, blue topaz is an excellent alternative - as long as it is properly represented ... and priced. Also, note that many aquamarine-colored synthetic spinels are erroneously sold as aquamarine. 
CITRINE -often called quartz topaz, citrine topaz, or topaz, all of which are misleading. It is yellow, amber, to amber brown. While a pleasing stone in terms of colour, and fairly durable, citrine is slightly softer and has less brilliance than precious topaz. It also lacks the subtle colour shading, the pinkier yellow or pinkish amber shades, which lend to precious topaz a distinctive colour difference. (Much citrine is made by heat-treating purple amethyst.) Citrine is also much less expensive than precious topaz. It should never be represented as topaz, which technically is "precious" or "imperial" topaz. Citrine is plentiful in all sizes, and can be made into striking jewellery, especially in very large sizes, for a relatively small investment.
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