Amethyst

Hardness: 7 on the Mohs scale. Color: Ranges from light lilac to deep purple, often with banding; sometimes heat-treated to become yellow (citrine) or green (prasiolite). Luster: Vitreous (glassy). Crystal Structure: Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Amethyst forms in volcanic rocks (often in geodes or vugs) or hydrothermal veins when silicon dioxide-rich fluids crystallize. The purple color is due to irradiation of iron impurities within the quartz structure. Geological age varies widely depending on the deposit, from millions to hundreds of millions of years old.

Predominantly used as a gemstone in jewelry (rings, necklaces, earrings, bracelets) and for ornamental carvings. Also popular in crystal collecting and decorative items. In ancient times, it was believed to prevent intoxication.

The name 'amethyst' comes from the Greek word 'amethystos,' meaning 'not intoxicated'. It is a popular and relatively affordable gemstone. Large geodes lined with amethyst crystals are significant decorative pieces. Brazil and Uruguay are famous for their large amethyst deposits. The color can fade with prolonged exposure to strong sunlight.

Identify by its characteristic purple color, vitreous luster, and hardness (it can scratch glass). It often occurs as pyramidal crystals in geodes or as massive forms. Commonly found in basalt flows, granite, and metamorphic rocks. Major sources include Brazil, Uruguay, Zambia, Bolivia, and parts of the United States. In the field, look for characteristic crystal habits and color in vugs or veins. Be aware of heat-treated varieties when purchasing for color.