gemstone

Tumbled amethyst with quartz and likely agate inclusions

Amethyst, purple quartz (SiO₂), with included/mixed quartz; crystalline variety of quartz

AI-generated identification · may be incorrect

Mohs hardness 7; purple, gray, and translucent brown-black zones with vitreous luster. Trigonal quartz structure; no prominent cleavage, conchoidal fracture; polished/tumbled surface obscures natural crystal form.

Identified September 8, 2026More gemstone →

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At a glance

Common name: Tumbled amethyst with quartz and likely agate inclusions
Scientific name: Amethyst, purple quartz (SiO₂), with included/mixed quartz; crystalline variety of quartz
Category: gemstone
Identified: September 8, 2026
Method: Standard

AI Estimated Value

Typically $3-$15 for a small tumbled stone; approximately $15-$50 if unusually attractive, strongly zoned, or unusually large.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Forms when iron-bearing quartz in volcanic cavities is irradiated and heated during hydrothermal activity, commonly alongside gray or milky quartz and agate. Most specimens formed in Mesozoic-to-Cenozoic volcanic regions, though exact age is unknown.

Uses & applications

Used as an ornamental stone, inexpensive cabochon, jewelry component, and mineral-collection specimen; tumbled pieces have modest decorative value.

Geological facts

The purple color comes mainly from irradiation-related defects involving iron impurities. Heating can turn amethyst yellow or orange, producing citrine-like material.

Field identification & locations

Identify by its glassy luster, hardness, purple quartz color, and lack of cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Uruguay, Zambia, Mexico, and the United States.