mineral

Amethyst and Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Purple/Violet (Amethyst) and Opaque White (Milky Quartz); Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Purple/Violet (Amethyst) and Opaque White (Milky Quartz)
Luster: Vitreous (glassy)

Identified July 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as linings in volcanic geodes. The purple color in amethyst is caused by irradiation of trivalent iron impurities within the quartz crystal lattice.

Uses & applications

Used extensively in jewelry, lapidary arts, mineral collecting, and as decorative display specimens. Historically used for intaglio and seals.

Geological facts

Amethyst was considered a precious stone in ancient times, on par with diamonds and rubies, until large deposits were found in Brazil. The name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identify by its hexagonal crystal points, purple hue, and lack of cleavage (it breaks in curved glass-like shards). Commonly found in Brazil, Uruguay, and Madagascar. Collectors look for deep violet saturation and crystal clarity.