Everything about Amethyst totally explained
Amethyst is a purple variety of
quartz often used as an
ornamental stone in
jewellery. The name comes from the
Ancient Greek a- ("not") and
methustos ("intoxicated"), a reference to the belief that the stone protected its owner from
drunkenness; the
ancient Greeks and
Romans wore amethyst and made drinking vessels of it in the belief that it would prevent
intoxication.
Chemistry
Amethyst is the purple variety of
quartz, its chemical formula is SiO
2.
In the 20th century, the color of amethyst was attributed to the presence of
manganese. However, since it's 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.
More recent work has shown that amethyst's coloration is due to ferric
iron impurities. Further study has shown a complex interplay of
iron and
aluminium is responsible for the color.
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.
Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are so similar to that of natural amethyst that it can't be differentiated with absolute certainty without advanced gemological testing (which is often cost-prohibitive). There is one test (which isn't 100 percent certain) based on "Brazil law twinning" (a form of
quartz twinning where right and left hand quartz structures are combined in a single crystal which can be used to identify synthetic amethyst rather easily. In theory however it's possible to create this material synthetically as well, but this type isn't available in large quantities in the market.
History
Amethyst was used as a
gemstone by the ancient
Egyptians and was largely employed in antiquity for
intaglios. Beads of amethyst were 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 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, Germany Exhibition of
1902.
Alternate terminology
Several descriptive terms have been coined in the gem trade to describe the 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.
Purple
corundum, or
sapphire of amethystine tint, is called Oriental amethyst, but this expression is often applied by jewelers to fine examples of the ordinary amethystine quartz, even when not derived from eastern sources. Professional gemological associations, such as the
Gemological Institute of America (GIA) or the
American Gemological Society (AGS), discourage the use of the term "Oriental amethyst" to describe any gem, as it may be misleading.
The Second Book of Pseudo-Albertus Magnus,
Of the Vertues of Certaine Stones, refers to amethysts by the name
Amarictus.
Geographic distribution
Amethyst is produced in abundance from the state of
Minas Gerais in
Brazil where it occurs in large
geodes within
volcanic rocks. It is also found and mined in
South Korea. The largest opencast amethyst vein in the world is in Maissau, Lower Austria. 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. One of the largest global amethyst producers is Zambia with an annual production of about 1,000 t.
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; Deer Hill and Stow,
Maine. It is found also in the
Lake Superior region. Amethyst is relatively common in
Ontario, and in various locations throughout
Nova Scotia, but uncommon elsewhere in Canada.
Value
Traditionally included in the cardinal, or most valuable, gemstones (along with
diamond,
sapphire,
ruby, and
emerald), amethyst has lost much of its value due to the discovery of extensive deposits in locations such as
Brazil. The highest grade amethyst (called "Deep Russian") is exceptionally rare and therefore its value is dependent on the demand of collectors when one is found. It is however still orders of magnitude lower than the highest grade sapphires or rubies (
Padparadscha sapphire or "pigeon's blood" ruby). Another variation involves the goddess
Rhea presenting Dionysus with the amethyst stone to preserve the winedrinker's sanity.
Further Information
Get more info on 'Amethyst'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://amethyst.totallyexplained.com">Amethyst Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
