mineral

Tumbled green agate (likely moss or chalcedony agate)

Cryptocrystalline quartz, SiO₂; likely green chalcedony with possible chlorite or iron inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent pale green to gray-green, waxy/vitreous luster, no visible cleavage, and a smoothly tumbled surface. Specific gravity is about 2.6; the rounded shape and uniform polish indicate human processing.

Identified August 31, 2026More mineral →

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At a glance

Common name: Tumbled green agate (likely moss or chalcedony agate)
Scientific name: Cryptocrystalline quartz, SiO₂; likely green chalcedony with possible chlorite or iron inclusions
Category: mineral
Identified: August 31, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a common tumbled stone; $10–$40 if unusually attractive, large, naturally patterned, or locality-specific.

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 rocks, commonly during the Cenozoic or older volcanic episodes; green coloration may come from chlorite, celadonite, or other inclusions. Exact identification and age require testing or locality information.

Uses & applications

Used for inexpensive jewelry, cabochons, beads, carvings, and decorative objects. Common tumbled pieces typically have modest collector value.

Geological facts

Agate is a variety of chalcedony, itself microcrystalline quartz. A waxy appearance, translucency, and resistance to scratching distinguish it from many similarly colored glass or plastic imitations.

Field identification & locations

Commonly found in volcanic terrains worldwide, including Brazil, Uruguay, India, Madagascar, Mexico, and the United States. Confirm with a quartz-level hardness test and magnification; dyeing or surface coatings are possible.