mineral

Unidentified polished dark stone with a possible quartz fragment

Indeterminate; appearance may reflect polished basalt, obsidian, or iron-rich rock, with a pale quartz/feldspar inclusion

AI-generated identification · may be incorrect

Dark gray-brown, strongly reflective surface with gold-blue iridescent highlights likely caused by polishing, coating, or thin-film interference; the loose pale piece appears translucent and glassy. Hardness and crystal structure cannot be determined reliably from the image.

Identified August 19, 2026More mineral →

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At a glance

Common name: Unidentified polished dark stone with a possible quartz fragment
Scientific name: Indeterminate; appearance may reflect polished basalt, obsidian, or iron-rich rock, with a pale quartz/feldspar inclusion
Category: mineral
Identified: August 19, 2026
Method: Standard

AI Estimated Value

About $5-$30 for a common polished or treated specimen; substantially more only if laboratory testing confirms a collectible mineral or gemstone.

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

The specimen may be a human-polished geological material; its original formation could be volcanic (basalt/obsidian) or metamorphic, but no geological age or process can be established visually.

Uses & applications

Potentially used as a decorative polished stone, cabochon, or display specimen; exact uses depend on confirmed composition.

Geological facts

The vivid metallic colors are not diagnostic of a specific mineral and can result from lacquer, oil, oxidation, or artificial iridescent treatment. The small tan fragment may be quartz, calcite, or feldspar.

Field identification & locations

Check for natural grain, conchoidal fracture, streak, hardness, and reaction to dilute hydrochloric acid; avoid destructive tests if treated. A clear photo of an untreated edge and tests for hardness, magnetism, and specific gravity would improve identification.