mineral

Polished blue-green chalcedony (likely moss or dendritic agate)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent blue-green to gray body with reddish-brown branching inclusions, waxy to vitreous luster, cryptocrystalline structure, and no cleavage. The rounded edges and smooth surface indicate tumbling or polishing.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited chalcedony in cavities of volcanic rocks; iron oxides and possibly manganese formed the brown dendritic patterns. Formation generally occurred during post-volcanic alteration, commonly in Cenozoic or older volcanic terrains.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and collectible polished specimens; value is mainly decorative rather than industrial.

Geological facts

The inclusions are mineral deposits, not organic moss or plants; branching patterns commonly result from dendritic iron/manganese oxides. Exact identification would benefit from locality data or testing.

Field identification & locations

Common sources include Indonesia, India, Madagascar, Brazil, Uruguay, and the western United States. Identify by its waxy translucency, lack of cleavage, conchoidal fracture, and resistance to scratching by steel; vinegar will not react.