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name comes from the Greek a (not) and methuskein ("to intoxicate"), a reference to
and Romans wore amethyst and made drinking vessels of it in the belief that
it would prevent intoxication.
In the 20th century, the color of amethyst was attributed to the presence of
manganese. However, since it is capable of being greatly altered and even
discharged by heat, the color was believed by some authorities to be from an organic
source. Ferric thiocyanate was suggested, and sulfur was said to have been detected
in the mineral.
On exposure to heat, amethyst generally becomes yellow, and much of the citrine,
cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst". Veins
of amethystine quartz are apt to lose their color on the exposed outcrop.
Amethyst was used as a gemstone by the ancient Egyptians and was largely
employed in antiquity for intaglios. Beads of amethyst are found in Anglo-Saxon
graves in England. It is a widely distributed mineral, but fine, clear specimens that
are suitable for cutting as ornamental stones are confined to comparatively few
localities. Such crystals occur either in the cavities of mineral-veins and in granitic
rocks, or as a lining in agate geodes. A huge geode, or "amethyst-grotto", from near
Santa Cruz in southern Brazil was exhibited at the Düsseldorf Exhibition of 1902.
Many of the hollow agates of Brazil and Uruguay contain a crop of amethyst crystals
in the interior. Much fine amethyst comes from Russia, especially from near
Mursinka in the Ekaterinburg district, where it occurs in drusy cavities in granitic
rocks. Many localities in India yield amethyst; and it is found also in Sri Lanka,
chiefly as pebbles.
Due to its popularity as a gemstone, several descriptive terms have been coined in
the gem trade to describe the varying colors of amethyst. "Rose de France" is usually
a pale pinkish lavender or lilac shade (usually the least sought color). The most
prized color is an intense violet with red flashes and is called "Siberian",
although gems of this color may occur from several locations other than Siberia,
notably Uruguay and Zambia. In more recent times, certain gems (usually of
Bolivian origin) that have shown alternate bands of amethyst purple with citrine
orange have been given the name ametrine.
Amethyst occurs at many localities in the United States, but these specimens are
rarely fine enough for use in jewelry. Among these may be mentioned Amethyst
Mountain, Texas; Yellowstone National Park; Delaware County, Pennsylvania;
Haywood County, North Carolina; and Deer Hill, and Stow, Maine. It is found also in
the Lake Superior district. Amethyst is relatively common in northwestern Ontario,
but uncommon elsewhere in Canada; it was selected as the provincial mineral of
Ontario in 1975.
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