mineral

Tumbled moss agate (likely dendritic/chalcedony agate)

Microcrystalline quartz, SiO₂, with iron/manganese-rich inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent gray-green to brown body with dark mossy inclusions, waxy to glassy luster, cryptocrystalline structure, and no visible cleavage. The smoothly rounded shape indicates tumbling and polishing.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rock, later depositing chalcedony and dendritic mineral inclusions. Agate formation commonly occurred from the Paleozoic through Cenozoic eras, depending on locality.

Uses & applications

Used for cabochons, beads, carvings, ornamental objects, and inexpensive collectible specimens; durable for jewelry but less valuable than transparent gemstone varieties.

Geological facts

“Moss agate” is a trade name rather than a single mineral species; its moss-like patterns are usually inclusions of iron or manganese oxides, chlorite, or hornblende—not biological moss.

Field identification & locations

Common sources include India, Brazil, Uruguay, Montana, and Madagascar. Identify it by translucency, curved banding or plume-like inclusions, waxy polish, and lack of fizz in dilute acid; glass imitations often show bubbles.