gemstone

Amethyst (rough crystal fragment)

Quartz, SiO₂; purple coloration from iron impurities and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple body with a vitreous luster and likely conchoidal fracture. Quartz is trigonal, has no cleavage, and a specific gravity near 2.65.

Identified August 22, 2026More gemstone →

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Physical properties

Mohs hardness 7; translucent purple body with a vitreous luster and likely conchoidal fracture. Quartz is trigonal, has no cleavage, and a specific gravity near 2.65.

Formation & geological history

Forms when silica-rich groundwater deposits quartz in volcanic cavities, commonly alongside agate and other minerals. Most specimens formed in relatively young volcanic provinces, though quartz itself is geologically widespread and ancient.

Uses & applications

Used as a semiprecious gemstone, ornamental material, and mineral specimen; also sold as tumbled stones and carvings. This small rough fragment has modest commercial value.

Geological facts

Amethyst is the purple variety of quartz and can fade with prolonged heat or strong sunlight. Its color commonly results from trace iron activated by natural radiation.

Field identification & locations

Identify it by purple color, glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; avoid relying on color alone because dyed glass and quartz are common imitations. Major sources include Brazil, Uruguay, Zambia, and Mexico.