Amethyst

Hardness: 7 on Mohs scale; Color: Purple (from pale lilac to deep violet); Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None, exhibits conchoidal fracture; Specific Gravity: 2.65

Amethyst is a variety of quartz that forms in hydrothermal veins, geodes, and igneous rocks. Its purple color is due to irradiation of iron impurities within the quartz crystal lattice. The geological age can vary widely, from millions to hundreds of millions of years, depending on the formation host rock.

Amethyst is widely used as a gemstone in jewelry (rings, necklaces, earrings, bracelets) due to its attractive color and durability. Larger specimens are popular as decorative items and for mineral collections. It's also used for its perceived metaphysical properties.

The name 'amethyst' comes from the Greek word 'amethystos,' meaning 'not drunken,' as it was believed to protect its wearer from intoxication. It was highly valued by ancient civilizations and royalty. Large amethyst geode discoveries have been made, particularly in South America.

In the field, amethyst is identified by its characteristic purple color and hexagonal crystal habit when found in geodes or vugs. It can scratch glass and steel due to its hardness. Common locations include Brazil (Rio Grande do Sul), Uruguay, Siberia (Russia), Zambia, Bolivia, and parts of the United States (e.g., Arizona, North Carolina). Look for purple crystals lining cavities in volcanic or metamorphic rocks.