Amethyst

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

Amethyst typically forms in hydrothermal veins or in the cavities (geodes) of igneous rocks, particularly basaltic lava flows. The purple color is due to irradiation of iron impurities within the quartz crystal lattice. Its formation can occur over millions of years, often in volcanic environments, with specific geological ages varying based on location.

Amethyst is primarily used in jewelry (rings, necklaces, earrings), as ornamental stones (cathedrals, geodes), and for collecting. Smaller polished stones are popular for alternative healing practices and as decorative items.

Amethyst is the most prized variety of quartz. Its name comes from the Greek word 'amethystos,' meaning 'not drunk,' as it was believed to protect its wearer from intoxication. It is the birthstone for February. Large quantities of high-quality amethyst were discovered in Brazil and Uruguay in the 19th and 20th centuries, making it more widely available.

In the field, amethyst can be identified by its distinctive purple color and its hardness (it scratches glass). It often occurs as pyramidal crystals or in geode formations. Common locations include Brazil, Uruguay, Canada (Thunder Bay), Siberia, Bolivia, and parts of the United States. Tips for collectors: Look for deep, even coloration and good clarity. Natural amethyst may fade with prolonged exposure to sunlight or heat.