Rock Identifier
Amethyst chip or polished fragment (Quartz, purple variety (SiO₂), likely mounted or attached to metal) — gemstone
gemstone

Amethyst chip or polished fragment

Quartz, purple variety (SiO₂), likely mounted or attached to metal

AI-generated identification · may be incorrect

The visible fragment is translucent purple-brown with a vitreous luster and apparent conchoidal fracture; quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65.…

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Physical properties

The visible fragment is translucent purple-brown with a vitreous luster and apparent conchoidal fracture; quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65. The pale edge may be metal or adhesive, so the image alone cannot confirm whether it is a loose gemstone, jewelry fragment, or coated piece.

Formation & geological history

Amethyst forms when iron-bearing quartz crystallizes in volcanic cavities, commonly in basaltic geodes, through hydrothermal fluids; deposits range from Precambrian to recent. Major sources include Brazil, Uruguay, Zambia, and Russia.

Uses & applications

Used as a jewelry gemstone, ornamental stone, and collector specimen; lower-grade material is used for carvings, beads, and geodes. Small fragments typically have modest value.

Geological facts

Purple color results mainly from irradiation and iron impurities, sometimes modified by heat treatment. Heating can turn amethyst yellow-orange, producing citrine-like material.

Field identification & locations

Check for purple zoning, quartz-like glassy luster, hardness, and lack of cleavage; glass imitations may contain bubbles and scratch more easily. A professional test is needed because the metal/adhesive and scale are unclear.