mineral

Tumbled feldspar-rich rock, possibly moonstone-bearing granite

Plagioclase feldspar (albite–oligoclase), with probable quartz and dark mica/amphibole; exact identification requires testing

AI-generated identification · may be incorrect

Hardness about 6–6.5 Mohs; gray-white with dark inclusions, vitreous to pearly luster, granular interlocking crystals, and no obvious cleavage visible in the rounded specimen. The silvery flash may indicate weak adularescence from moonstone feldspar.

Identified September 10, 2026More mineral →

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At a glance

Common name: Tumbled feldspar-rich rock, possibly moonstone-bearing granite
Scientific name: Plagioclase feldspar (albite–oligoclase), with probable quartz and dark mica/amphibole; exact identification requires testing
Category: mineral
Identified: September 10, 2026
Method: Standard

AI Estimated Value

Approximately $1–$10 as a common tumbled specimen; about $10–$50 if it displays attractive genuine adularescence or has verified gem-quality moonstone content.

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

Likely crystallized slowly from silica-rich magma in a coarse-grained igneous body, potentially granite or pegmatite; such rocks commonly formed in Precambrian to Phanerozoic continental crust. Surface rounding appears human-produced by tumbling or natural abrasion.

Uses & applications

Used mainly as a teaching or collector specimen; feldspar-rich rocks are also used as aggregate, dimension stone, and ceramic/glass raw material. If genuine moonstone is present, cleaner translucent pieces may be cut for jewelry.

Geological facts

The image alone cannot distinguish moonstone from ordinary reflective feldspar, quartz, or mica. A glass-scratch test, streak, cleavage inspection, and close examination of the flash under changing light would improve identification.

Field identification & locations

Look for feldspar’s two cleavage directions, pale streak, hardness near 6, and blocky grains; quartz is harder and lacks cleavage. Comparable material occurs in granites and pegmatites worldwide, including India, Madagascar, Norway, and the United States.