gemstone

Amethyst cluster/geode

Quartz, crystalline silica (SiO₂), purple variety colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, transparent to translucent purple quartz crystals with conchoidal fracture and no cleavage; specific gravity about 2.65. The specimen appears to have a gray-brown druzy or host-rock rind and darker violet crystal tips.

Identified September 13, 2026More gemstone →

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At a glance

Common name: Amethyst cluster/geode
Scientific name: Quartz, crystalline silica (SiO₂), purple variety colored mainly by iron impurities and irradiation
Category: gemstone
Identified: September 13, 2026
Method: Standard

AI Estimated Value

About $10–$50 for a common hand-sized cluster; roughly $75–$300+ for larger, sharply terminated, intensely colored, or exceptional locality specimens.

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 silica-rich groundwater deposits quartz crystals in cavities of volcanic rocks, especially basaltic lava vesicles. Most commercial material formed during Cenozoic volcanic activity, commonly in Brazil and Uruguay.

Uses & applications

Used for jewelry, carvings, display specimens, and metaphysical collecting; large clusters have decorative value. It is not generally used as a construction stone.

Geological facts

Amethyst’s purple color can fade with prolonged heating or strong sunlight; heat treatment may produce yellow citrine. Crystal color is often strongest near exposed tips or cavity surfaces.

Field identification & locations

Identify it by six-sided quartz crystals, glassy luster, purple zoning, and hardness sufficient to scratch ordinary glass. Common sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.