sedimentary

Moss Agate

Agate (Silicon Dioxide, SiO2) with dendritic inclusions

Hardness: 6.5-7 (Mohs); Color: Clear or milky white with green, brown, or black inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Hardness: 6
Color: Clear or milky white with green, brown, or black inclusions
Luster: Vitreous to waxy

Identified January 22, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica in rock cavities (vesicles) or cracks. The 'moss' effect is created by dendritic inclusions of manganese or iron oxides that crystallize as the silica solidifies. It occurs in volcanic environments over millions of years.

Uses & applications

Used primarily in jewelry, cabochons, and ornamental carvings. It is a popular collector's stone and is often used in artisan wire-wrapped pendants like the one shown.

Geological facts

Despite its name, Moss Agate does not contain organic matter; the plant-like patterns are strictly mineral. It was historically called 'Mocha Stone' after the city of Mocha in Yemen.

Field identification & locations

Identify in the field by its semi-transparent body and branching, plume-like internal inclusions. It is commonly found in India, Brazil, Uruguay, and the western United States. To differentiate from other jaspers, check for areas of translucency when held to light.

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