gemstone

Polished moss agate (likely dendritic agate)

Chalcedony, microcrystalline quartz (SiO₂), with inclusions of manganese/iron oxides or hornblende

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent gray-green to cream with black, moss-like inclusions; vitreous to waxy luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded, glossy form is polished, not natural weathering.

Identified September 15, 2026More gemstone →

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At a glance

Common name: Polished moss agate (likely dendritic agate)
Scientific name: Chalcedony, microcrystalline quartz (SiO₂), with inclusions of manganese/iron oxides or hornblende
Category: gemstone
Identified: September 15, 2026
Method: Standard

AI Estimated Value

Approximately $5–$25 for a small polished cabochon; $30–$100+ for unusually attractive patterning or larger quality pieces.

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 rock, while mineral impurities create branching inclusions; commonly Cenozoic to older volcanic-hosted material. Similar-looking stones may be sold as dendritic agate or “tree agate.”

Uses & applications

Used for cabochons, beads, carvings, and lapidary collectibles; occasionally in ornamental objects. Commercial value is generally modest unless pattern, translucency, and polish are exceptional.

Geological facts

Moss agate’s inclusions are mineral patterns rather than organic moss or fossils. Black dendrites commonly contain manganese oxides, while green tones may involve chlorite or hornblende.

Field identification & locations

Identify by its glassy polish, waxy translucency, hardness, and branching inclusions; it should not show crystal faces or strong cleavage. Major sources include India, Brazil, Uruguay, the United States, and Australia.