mineral

Amethyst cluster (quartz geode fragment)

Amethyst, purple variety of quartz; silicon dioxide (SiO₂) colored mainly by iron-related defects

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, hexagonal quartz crystals, and no true cleavage; purple crystal tips contrast with a gray-white quartz and darker matrix, likely basalt or another host rock. Specific gravity is about 2.65.

Identified August 25, 2026More mineral →

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At a glance

Common name: Amethyst cluster (quartz geode fragment)
Scientific name: Amethyst, purple variety of quartz; silicon dioxide (SiO₂) colored mainly by iron-related defects
Category: mineral
Identified: August 25, 2026
Method: Standard

AI Estimated Value

Approximately $10–$40 for a common small cluster; $50–$200+ for larger, vivid, well-formed specimens, especially from notable localities.

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 rock, commonly during late-stage hydrothermal activity. Individual deposits range from relatively young volcanic settings to Paleozoic and older rocks, depending on locality.

Uses & applications

Used as a specimen, ornament, and gemstone; fine transparent material is faceted, while clusters are sold for décor and mineral collections. It has little construction or industrial value compared with ordinary quartz.

Geological facts

Amethyst’s purple color can fade with prolonged heat or intense sunlight; heating may produce yellow or orange citrine-like colors. Large commercial deposits occur in Brazil, Uruguay, Zambia, and Morocco.

Field identification & locations

Identify it by purple, glassy quartz crystals with six-sided points and hardness sufficient to scratch ordinary glass; unlike fluorite, it lacks prominent cleavage. The image appears to show a small natural cluster on matrix, though locality cannot be determined visually.