mineral

Polished agate (likely moss or plume agate)

Microcrystalline quartz, mainly chalcedony (SiO₂), with possible calcite or quartz vein inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent gray-brown body with cream-white banding or vein-like inclusions, waxy to glassy luster, cryptocrystalline structure, and no obvious cleavage. The wet surface enhances translucency and gloss.

Identified September 15, 2026More mineral →

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At a glance

Common name: Polished agate (likely moss or plume agate)
Scientific name: Microcrystalline quartz, mainly chalcedony (SiO₂), with possible calcite or quartz vein inclusions
Category: mineral
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $3–$20 for a common small polished piece; $25–$100 or more for unusually attractive patterns, large size, or confirmed provenance.

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 fills cavities in volcanic rocks, depositing layers of chalcedony and quartz over time; individual bands may form over millions of years, commonly in Cenozoic to older volcanic terrains.

Uses & applications

Used for cabochons, beads, carvings, lapidary pieces, and inexpensive collectibles; durable polished agate is also used for decorative objects and occasional industrial bearings.

Geological facts

Agate’s patterns result from repeated changes in silica chemistry, impurities, and fluid flow. The specimen appears tumbled or naturally water-smoothed rather than freshly fractured.

Field identification & locations

Identify by its waxy translucency, curved or irregular banding, high hardness, and resistance to scratching by steel; common sources include Brazil, Uruguay, Mexico, India, and the western United States. Exact variety is uncertain from one image.