mineral

Polished amethyst and dark polished stone

Amethyst: purple quartz, SiO₂; dark specimen: likely black tourmaline, obsidian, or dark agate (uncertain from image)

AI-generated identification · may be incorrect

Amethyst is purple with white quartz matrix, vitreous luster, Mohs hardness 7, and hexagonal quartz structure with no cleavage. The upper stone is opaque black-green, smoothly polished, and likely has hardness around 6–7.

Identified August 28, 2026More mineral →

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At a glance

Common name: Polished amethyst and dark polished stone
Scientific name: Amethyst: purple quartz, SiO₂; dark specimen: likely black tourmaline, obsidian, or dark agate (uncertain from image)
Category: mineral
Identified: August 28, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 each for common polished palm stones; attractive, larger or unusually patterned pieces may reach $50–$100.

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

Amethyst forms when iron-bearing quartz crystallizes in gas cavities of volcanic rocks, commonly during the Mesozoic to Cenozoic. The dark stone may be volcanic glass, chalcedony, or tourmaline and cannot be securely identified visually.

Uses & applications

Amethyst is used in jewelry, carvings, display specimens, and crystal collecting; the dark stone is mainly ornamental. Small polished palm stones typically have modest commercial value.

Geological facts

Amethyst’s purple color results from iron impurities and irradiation. Heating can turn it yellow, producing citrine.

Field identification & locations

Identify amethyst by purple quartz crystals or a granular white quartz matrix and hardness sufficient to scratch glass. Common sources include Brazil, Uruguay, Zambia, and Mexico; confirm the dark stone with streak, hardness, translucency, and specific-gravity tests.