Rock Identifier
Purple quartz fragments, likely amethyst (Amethyst (quartz, SiO₂)) — mineral
mineral

Purple quartz fragments, likely amethyst

Amethyst (quartz, SiO₂)

AI-generated identification · may be incorrect

Usually translucent purple with a vitreous luster, conchoidal fracture, and no cleavage; Mohs hardness 7, trigonal crystal structure, specific gravity about 2.65. The pictured small, irregular polished or naturally broken fragments are consistent with quartz, though lighting limits certainty.

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Physical properties

Usually translucent purple with a vitreous luster, conchoidal fracture, and no cleavage; Mohs hardness 7, trigonal crystal structure, specific gravity about 2.65. The pictured small, irregular polished or naturally broken fragments are consistent with quartz, though lighting limits certainty.

Formation & geological history

Purple coloration comes from iron-related defects and irradiation in silica-rich hydrothermal cavities, commonly in volcanic rocks; specimens range from Precambrian to recent geologic settings. Common sources include Brazil, Uruguay, Zambia, and Mexico.

Uses & applications

Used for jewelry, ornaments, crystal collections, and decorative objects; lower-grade material is sold as tumbled stone or aggregate. These small fragments generally have modest commercial value.

Geological facts

Amethyst is the purple variety of quartz and can fade with prolonged strong heat or sunlight. Its color may overlap with purple glass, fluorite, or dyed quartz, so confirmation requires testing.

Field identification & locations

Check for glassy luster, hardness sufficient to scratch ordinary steel or glass, and conchoidal fracture; fluorite is softer and commonly shows cleavage. Estimated value: about $1–$10 for this small mixed fragment group, or $10–$50+ if confirmed natural, attractive amethyst.