Home > Amethyst (Molecule of the Month for January 2000 )

Picture of Amethyst

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Amethyst structure
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Picture of Amethyst

SiO2

Amethyst's importance originates in antiquity.

In the Bible
an amethyst is worn on the breastplate of Aaron, the high priest of the Hebrews. This amethyst represented the prophet Math, who was filled with the desire to please God and who had the gift of tongues.
In Greek mythology
Dionysus, the god of wine and song, was angry and vowed to slay the first mortal who crossed his path. That unlucky mortal was Amethyst, a beautiful maiden.
However, Artemis (goddess of virginity and the hunt) intervened and transformed Amethyst into white stone. When Dionysus saw what had happened, he repented and poured wine over the stone, staining the top of it purple. That is why the top of amethyst is purple and the bottom is white.
Though the story has other variations such as: The Goddess Diana transformed a beautiful young maiden, Amethyst, into a statue of pure quartz in an effort to protect her from vicious tigers created by the vengeful God, Dionysus. Dionysus having looked upon the results of his actions wept remorseful tears of wine upon the statue endowing the stone with the rich purple hue we know today. Dionysus as it happens was the God of Intoxication
In folklore and mythology
amethyst has many supernatural powers.
Amethyst purportedly Brings luck, Ensures constancy, Protects against magic, Prevents home-sickness, Protects against drunkenness, (the Greek word amethustos means "not drunk")
Leonardo da Vinci wrote that the gem dissipates evil thoughts and quickens the intelligence -- high praise indeed.

Amethyst is a variety of quartz with purple coloration which is caused by impurities of iron or manganese.
Color: Amethyst occurs in a wide range of purple shades. Index of refraction: 1.544-1.553 Birefringence: 0.009. The purple color can be throughout or can be in bands with white quartz.
Its color and beauty are without rival, even from other much more expensive purple gems. Purple is the color of royalty. The rich and powerful have worn it as a mark of rank for hundreds of years. Even today as an affordable gem available in a wide selection of cut stones it has a regal air.
Amethyst is found in many areas around the world, including Mexico, Brazil, Uruguay, Africa, and Russia. In the United States, Amethyst can be found in Montana, Arizona, Colorado, Maine, and New Jersey.
In Canada, Amethyst is found near Thunder Bay and in Nova Scotia. One typical feature of Amethyst from Thunder Bay is its reddish coloration, caused by an internal coating of red hematite (iron).
Russian stones ( form the Urals) are very clear and dark. They are cut for fine expensive gemstones and gave rise to the term Siberian to indicate the very best Amethyst. Uruguayan and Bahain represent high medium and low grades, regardless of the source.
Amethyst crystals are hexagonal and can occur as tall prismatic crystals or short stubby ones (Crystal system: trigonal). The crystals often have horizontal striations on their sides or faces. Hardness: 7 Cleavage: none
Amethyst is often cut as brilliant round and/or oval stones to maximize the color. Other cuts are used when the crystal shape would not yield a fine oval or round.
Amethyst is one of several gem quartz varieties. The others are :
Citrine. A yellow to orange variety, rare in nature but often created by heating Amethyst.
Rock crystal, a clear stone, occasionaly used as a gem.
Rose quartz, a pink stone, sometimes cut as a cabochon.
Smoky quartz, the brown to gray quartz stones, sometimes in error called smoky topaz.

Quartz (Amethyst) is a low pressure/temperature polymorph of SiO2. At high temperatures, quartz exists in the beta form, with hexagonal symmetry. At lower temperatures there is a displacive phase transition to a distorted structure with trigonal symmetry (alpha form).

If you have Apple's QuickTime software click here to see an interactive QTVR crystal of Amethyst.

Formal Chemical Name (IUPAC)

Update by Karl Harrison
(Molecule of the Month for January 2000 )