gemstone

Moss Agate

Silicon Dioxide (Chalcedony with green mineral inclusions), SiO2

Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, translucent to opaque transparency, trigonal crystal system, conchoidal fracture with no true cleavage, and a specific gravity around 2.58 to 2.64.

Identified July 30, 2026More gemstone →

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Physical properties

Formation & geological history

Formed from weathering of volcanic or metamorphic rocks where silica-rich groundwater fills cavities and fissures, depositing microscopic quartz crystals along with green hornblende, chlorite, or other dendrite-forming minerals.

Uses & applications

Widely used in jewelry making, as tumbled stones, for decorative carvings, and highly prized by mineral and crystal collectors.

Geological facts

Despite its name, moss agate does not contain any organic matter; the 'mossy' or dendritic patterns are actually mineral impurities like manganese or iron oxides that resemble plant growth.

Field identification & locations

Easily identified visually by its translucent chalcedony body filled with green, fern-like or moss-like inclusions. Found globally, notably in India, the United States, Brazil, and Australia.

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