Amethyst.

Color: Pale lavender to deep purple
Chemical composition: SiO2 silicon dioxide
Moh’s Hardness: 7
Transparency: Transparent
Luster: Vitreous
Fracture: Conchoidal, very brittle
Crystal system: Hexagonal (trigonal) with hexagonal prisms
Specific gravity:  2.63-2.65
Streak: White
Refractive index: 1.544-1.553
Dispersion: 0.013
Pleochroism: Very weak; violet, gray-violet
Fluorescence: Weak; greenish
Occurrence: Africa, Brazil,  Britain, Canada, India, Malagasy Republic, Siberia, Sri Lanka, United States, Uruguay
Astrology:  February birth stone, connected with Aquarius; in India, connected with Saturn
Chakra: 6th and 7th, the brow and crown

Amethyst, the most precious variety of gem-quartz, is a fairly common crystal. In general, the darker amethysts are more highly valued than the pale stones.  Quartz can form in nearly any type of rock, but amethyst often forms in the cavities of volcanic rock.  Nearly 130 million years ago, in Uruguay and Southern Brazil (the main sources of the gem), gas bubbles became trapped in cooling silica-rich lava and formed cavities. At a later point, water percolating through the rock dissolved some of the silica and deposited it as amethyst crystals inside these hollows.  Amethyst’s distinctive color is caused when a few iron atoms replace the silicon atoms in the quartz solution. Amethyst is often found inside geodes (those cavities in volcanic rock), though it’s also found in alluvial deposits. Amethyst is sometimes heat-treated to intensify its color. Amethyst takes its name from the Greek, amethustos, “not drunken.”  A well-known Roman myth tells of the wine god Bacchus who, feeling slighted by humankind, set his tigers on a young nymph named Amethyst who was on her way to worship at the shrine of the goddess Diana.  Diana intervened, turning the young woman into a beautiful crystal.  Bacchus, filled with remorse, poured his wine over the crystal, giving it its purple color.  Another theory states that the Greeks carved drinking vessels from large amethyst crystals, so that they could appear to be drinking wine and yet could actually be drinking water and so remain sober.  The Roman women had an altogether different use for the stone. They wore amethysts to keep their husbands’ affection. In 11th-century Germany, this belief was somewhat reversed: Amethyst was said to help a man attract noble women. The Egyptians, though, considered amethyst symbolic of the intellect.  Cleopatra was said to wear an amethyst signet ring engraved with the image of the Persian god of “The Divine Idea,” a source of love and enlightenment.  And in Peru, amethyst was used in charms against witchcraft. Other beliefs held that amethyst symbolized peace of mind, and if engraved with either a sun or full moon, it protected against death by poison.  During the Renaissance, it was believed that an amethyst engraved with a bear was a charm against demons. Biblically, amethyst was said to be one of the gemstones in the breast plate of the High Priest. The Roman Catholic Church connected it with Christ’s blood transforming into wine. As a symbol of Christ, it was worn by the bishops in their ceremonial rings.  The Church also dedicated the stone to St. Valentine.
Metaphysically, amethyst is known as a protective crystal with a highly spiritual vibration that encourages love of the divine energy. It’s also a stone whose calm energy aids in meditation is considered helpful when trying to break an addiction. According to Ayurvedic healers, amethyst gives off a minute electrical charge that helps bring the body back into electrochemical balance.  It also transmits short ultraviolet light waves that help alleviate anxiety and anger by absorbing the any excess heat in the body. With a hardness of 7, amethyst is a fairly tough stone, but it’s brittle and can crack, so be gentle if you’re wearing a bracelet of amethyst beads.  And be careful not to leave amethyst in the sun, as sunlight can fade its color. In Victorian jewelry, amethyst was often paired with pearls. It’s also been strung with turquoise and jade, and works beautifully with peridot and citrine. The darker amethysts will provide a rich contrast in multicolor pieces when combined with stones like amber, chrysoprase, lapis lazuli, and carnelian.