Amethyst

species QUARTZ

The violet, purple to almost pink variety of quartz is called amethyst, and ancient name derived from the Greek meaning "not drunken," as it was believed to protect those who wore if from drunkeness. it is the most highly prized varety of quartz
Appearance the Typical color is a rich, violet-purple, often distributed in patches or bands. it can also be quite pale, but is generally the same basic color, without any overtones. It is given both oval and drop mixed cuts, step cuts, and other types of cuts used for colored stones. Specimens of good color but with too many inclusions are cut en cabochon. Stones of 10 or  so carats in weight are often found and even larger ones are not rare. Amethyst normally has good luster and transparency. Well-formed, Chaacteristically colored groups of crystals (geodes andruses) are even used in their natural state as ornaments.
Distinctive features The distribution of the color, in striking patches and bands, is characteristic. When the stones contain inclusions, a series of discountinuous, wavy parallel lines, visible with a lens, indicateds that they are certainly amethyst.
As with nearly all quartzes, the interference figure has a distinctive profile, which usually makes identification immediate. Quartz may resemble some violet synthetic corundum, but the latter turns reddish in strong artficial light or full sunlight. Amethyst can also look vaguely similar to violet cordierite, which also has a strong, distinctive pleochroism. The much rarer violet scapolite mahy look quite similar, and its physical characteristics are almost the same as those of quartz. Therefore they can only be distinquished by and expert.
Occurrence The finest amethysts come (in great quantities) from Brazil and neighboring Uruguay, from the United States, Madagascar, and the Soviet Union, India, Australia, South Africa, and mayn other countries.
Value A few centuries ago, deep-colored amethyst was highly prized. Its value fell greatly with the discovery of the large Brazilian and Uruguayan deposits at the end of the nineteenth century. Now relegated to the status of a secondary gem, its value is quite low.
Simulants and synthetics  Amethyst was much imitated by colored glass in the past, when it was more costly. Nowadays, despite the limited value of the natural stone,fair quantities of synthetic amethyst are produced, using the knowledge acquired in the production of synthetic quartz for technological purposes. The cost of the synthetic product is not much less the that of the nutural gemstone.