Information For precious and semi precious gemstones
Stone : Amethyst
Moh's Hardness : 7
Origin Locations : Minas Gerais, Brazil; Nigeria, Tanzania, Mozambique, Zambia, Namibia, Africa; Sir Lanka, Madagascar; Russia; Mexico; Canada; Binbee near Bowen, QLD, Kuridala QLD, Australia
Treatments : None, Heating
Clarity : Eye Clean to Included
Color : Various shades of violet, pale red-violet, purple. See a colour chart for amethyst here.
Cleavage : None
Crystal System : (Trigonal), hexagonal prisms
Chemical Composition : SiO2 - silicon dioxide
Refractive Index (RI) : 1.544 - 1.553
Density : 2.65
Birthstones : Amethyst is the birthstone for February.
Amethyst is the ayurvedic birthstone for February.
Amethyst is the zodiac stone for Pisces.
Amethyst is the stone for the 6th anniversary.
Comments : Amethyst is instantly recognisable for its lovely violet and purple colors and has long been used in jewelry. It is perhaps the most valuable stone in the quartz family. The name is believed to come from the Greek meaning "not drunken" and was indeed used as an amulet against drunkeness. In past times and even today, amethyst is a favorite gemstone within the christian church, being worn by priests and officals in rings. Historically, amethyst was much rarer then it is today and was highly regarded and valued and considered to be a very precious gem along side emeralds, rubies and sapphires. Today, large deposits are known and this has made it very attainable.
Amethyst is found in many places but some of the best comes from Brazil, Uruguay and Zambia. The amethyst from each location can be quite distinct and recognisable, for example, top Uruguayan amethyst is very highly saturated and has strong blue-purple colors. Some stunning stone called "Siberian" amethyst came from Russia but the deposits have long since been mined out. This particular siberian amethyst had red tones and the name is now (probably too often and incorrectly) used for amethyst that has similar red-purple tones. The term is applied perhaps a little too liberally these days in the market place.
Amethyst is usually found as crystals, either loose or in geodes. These geodes are like hollow rocks with the inside being coated in amethyst crystals. Some of these geodes can attain sizes as big as watermelons and even as big as a person! They are cut in halves and the crystals removed if they are found to be of good facet grade. These geodes are often used as displays and are absolutely beautiful glittering in the candlelight. High quality amethyst facet rough is becoming expensive as costs of mining goes up.
Amethyst can also be heat treated at around 878-1382 degrees F to improve colour or change the colour completely to yellow (citrine), red-brown and even green. The coloring agent in amethyst is iron.
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