Mostly we think of faceting when we see these stones. However they may also be cabbed, tumbled, carved, used in inlays, cut into spheres and used as caps on triplets.

Optical quartz is used for making "crystal balls". Although the amature can make them on his sphere-making machine, they will rarely be more than two inches in diameter because large material is very scarce and commands a higher price. Clear quartz is very reasonable in price. Most comes from Brazil but a lot comes from the U.S.

Smokey quartz is usually easily available and is moderate in price. The lighter colors are cheaper, but the medium golden brown is most desireable. The darker varieties make beautiful carvings. For the cabber, a lovely effect is obtained by flattening the polishing a vivid piece of abalone and topping it with a thin dome of smokey quartz.

Rutilated quartz is also easy to buy. The needles can very from golden to deep coppery-red. Large cabochons show the rutile inclusions best. Try freeform cabs- carefully studying the specimen so that the most spectacular effects may be obtained. In a few cases, the rutile needles can work loose in cabbing because they are not firmly bonded to the quartz. Soaking it in a solution of half water and half water glass (sodium silicate) for a few days and then drying thoroughly will solve this problem.

Although not easy to find any more, clear quartz with black Tourmaline inclusions still can be bought. It makes striking cabs as well as specimens. Rose quartz has a slightly milky or cloudy appearance usually, a deep pink is best for cuttin cabs. This is beautiful carving material. The best grades are scarce and high priced. Some rose quartz will star, with either a six or twelve ray. It usually needs a darker backing to show the star. Spheres are the best way to display the star.

Citrine, in yellow and golden brown hues, is reasonable for the cabbor; but the orange-red and darker rods are quite expensive and used for faceting.

Amethyst is the most valueable form of quartz, depending on the color and clarity. The best grade is known as "Siberian", regardless of its source. "Rose de France" is an attractive pale purplish-pink amethyst. It is moderately priced and can be used for tumbling, faceting, carving, etc. Really fine amethyst is high priced and hard to come by. There is plenty of material around the world, but large commercial cutters buy all the stones they come by. Many gem-producing nations encourage their workmen to cut amethyst at home. This competition makes it hard for the amatuer.

Amethyst is frequently color-zoned, banded with colorless and colored material. It can also have uneven, blotchy colors running though clear sections. This makes extremely lovely cabs. I oil the stone lightly and hold it to a bright light. If you can't see the patterns in it, you may have to slab the stone thinner. Amethyst cabs were popular around the turn of the century. They have started to make a comeback. Engraved amethyst seals were also widely worn and used at one time. Carvings of it have been made for centuries; Chinese snuff bottles are highly prized by collectors. Tumbled Amethyst is used in gem "trees". Small sections of amethyst-lined geodes are used as pendants and brooches.

All of these crystals should be worked very gently, as they are very brittle.

Feb 22, 2010
www.postzambia.com

KAGEM Mine in Ndola has announced the discovery of an "exceptional" 6,225-carat rough emerald, a piece that the company expects will yield a number of significantly sized cut gems. The emerald was recovered during normal mining operations on February 5, this year and experts for Gemfields have been examining the piece to determine its value and significance before deciding upon its future.

According to a press release issued on Monday, Gemfields, the London-based gemstone producer which owns Kagem Mine said the rough emerald has been dubbed Insofu, which means elephant, in honour of the World Land Trust's Elephant Corridor Project and in consideration of the stone's unusually large size.

"This is a unique find," Gemfields chief executive said officer Ian Harebottle. "The Insofu displays wonderful colour and good translucency. Its sheer size, rich colour and fine protective biotite shell makes it difficult to see deep into the gem. However, all indications suggest that the core of the emerald is competent and that it should yield a number of cut gems of significant size."

Gemfields focuses on the consistent supply of what it describes asethically produced emeralds, which are mined under a rigorous set of standards in regards to fair trade, environmental, social and safety practices. It states that it guarantees the provenance of every gem through a full disclosure and certification programme.

The largest uncut emerald believed to have been found was in Carnaiba, Brazil in 1974 and it was an incredible 86,136-carat natural beryl crystal. The stone was eventually valued at US $1,120,080 while the largest emerald crystal ever discovered was 7,025 carats and was found in a mine in Colombia.