mineral

Moss Agate / Carnelian Agate

Silicon Dioxide (SiO2) with iron and manganese inclusions

Hardness: 6.5-7 on Mohs scale. Color: Translucent orange to reddish-brown with green/black dendritic inclusions. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Hardness: 6
Luster: Vitreous to waxy

Identified March 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities of volcanic rocks (basalt or andesite) where silica-rich groundwater precipitates over time. The orange color is due to iron oxide (hematite), while the green 'moss' inclusions are typically manganese or iron silicates. Geological age varies by locality from millions to hundreds of millions of years.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and jewelry. Also popular as a landscape stone, for metaphysical collecting, and as a durable material for decorative carvings.

Geological facts

Moss agate is not a true fossil; the plant-like patterns are actually inorganic chemical formations called dendrites. It has been used since ancient times for amulets and was particularly prized in the 18th century as a good luck stone for gardeners.

Field identification & locations

Identify in the field by its translucency when held to light, its waxy texture when wet, and the characteristic conchoidal (shell-like) fracture. Commonly found in riverbeds and gravel pits in areas with ancient volcanic activity like the Pacific Northwest, Brazil, and India.

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