gemstone

Polished moss agate

Moss agate, a microcrystalline quartz variety (SiO₂) with green chlorite/actinolite or iron-manganese inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent to opaque gray-white chalcedony with branching green, moss-like patterns; vitreous to waxy luster, no visible cleavage, cryptocrystalline structure, specific gravity about 2.6.

Identified August 22, 2026More gemstone →

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At a glance

Common name: Polished moss agate
Scientific name: Moss agate, a microcrystalline quartz variety (SiO₂) with green chlorite/actinolite or iron-manganese inclusions
Category: gemstone
Identified: August 22, 2026
Method: Standard

AI Estimated Value

Approximately $10–$40 for a common polished specimen; $50–$150+ for larger pieces with exceptional patterning and translucency.

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 and fractures in volcanic rocks, trapping mineral inclusions that create dendritic patterns. Most deposits are Cenozoic to younger, though host-rock ages vary.

Uses & applications

Used for cabochons, pendants, carvings, and ornamental objects; attractive patterned pieces have moderate lapidary and collector value.

Geological facts

Despite its appearance, the green markings are mineral inclusions rather than plant fossils. It is a variety of agate/chalcedony, not typically true banded agate.

Field identification & locations

Identify by its waxy silica surface, conchoidal fracture, lack of cleavage, and natural mossy inclusions; common sources include India, Brazil, Uruguay, the United States, and Australia. The pictured piece appears cut and polished.