mineral

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple coloration commonly from iron-related defects and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous luster, white-to-lavender translucent crystals, conchoidal fracture, no cleavage, hexagonal crystal structure, specific gravity about 2.65. The specimen also appears to contain white crystalline quartz and minor dark inclusions, possibly iron oxides or host-rock minerals.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basaltic lavas; purple quartz develops through trace iron and natural radiation. Individual deposits may range from relatively young volcanic-hosted cavities to older hydrothermal systems.

Uses & applications

Used for mineral collecting, carvings, ornaments, and jewelry; quartz is also important industrially in glass, electronics, and abrasives.

Geological facts

Amethyst is the purple variety of quartz and owes its color mainly to ferric iron-related defects. Heating can turn some amethyst yellow or orange, producing citrine-like material.

Field identification & locations

Identify by purple hexagonal quartz crystals, glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and Mexico. Exact locality cannot be determined reliably from the image.