mineral

Tumbled agate (likely moss or plume agate)

Microcrystalline quartz, primarily chalcedony (SiO₂), with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown, honey, gray, and cream coloration; waxy to vitreous luster; translucent edges; cryptocrystalline quartz with no obvious cleavage and conchoidal fracture. The rounded, glossy surface indicates tumbling and polishing.

Identified August 29, 2026More mineral →

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At a glance

Common name: Tumbled agate (likely moss or plume agate)
Scientific name: Microcrystalline quartz, primarily chalcedony (SiO₂), with iron-oxide and other mineral inclusions
Category: mineral
Identified: August 29, 2026
Method: Standard

AI Estimated Value

About $3–$20 for a common tumbled specimen; $20–$100+ if the pattern, translucency, or locality is unusually attractive.

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

Agate forms when silica-rich groundwater fills cavities in volcanic rock, depositing chalcedony in layers around inclusions or earlier mineral growths. Individual deposits range from Paleozoic to recent in age and occur worldwide.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary collections; durable agate is also used for polished decorative objects and historical precision-tool surfaces.

Geological facts

The internal plume or moss-like patterns are mineral inclusions rather than true organic moss. Brown coloration commonly results from iron oxides or hydroxides.

Field identification & locations

Identify agate by its waxy polish, translucency, curved banding or dendritic inclusions, and hardness sufficient to resist scratching by steel. Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the United States.