sedimentary

Green Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe)

Hardness: 6.5-7 (Mohs scale); Color: Clear/translucent grey with dark green 'moss' inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Clear/translucent grey with dark green 'moss' inclusions
Luster: Vitreous to waxy

Identified April 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from groundwater in cavities within igneous rocks. The dendritic inclusions are formed by oxides of manganese or iron during the crystallization process. Found in volcanic regions.

Uses & applications

Used primarily for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for metaphysical collectors and crystal healing enthusiasts.

Geological facts

Despite its name, Moss Agate is technically not a 'true' agate because it lacks the concentric banding essential to agates; it is a dendritic chalcedony. The 'moss' is not organic matter, but mineral filaments.

Field identification & locations

Identify in the field by its translucent body combined with green, branching, plant-like inclusions. It is found globally, with famous deposits in Montana (USA), India, and Brazil. Common in riverbeds near volcanic activity.

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