mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Hardness: 6.5-7 Mohs; Color: White or clear base with green mossy inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: White or clear base with green mossy inclusions
Luster: Vitreous to waxy

Identified May 7, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6.5-7 Mohs; Color: White or clear base with green mossy inclusions; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed from the weathering of volcanic rocks and the deposition of silica from hydrothermal fluids. The dendritic moss-like patterns are caused by traces of manganese or iron oxides, often associated with chlorite and hornblende.

Uses & applications

Mainly used in jewelry, ornamental carvings, and metaphysical collecting. Historically used as a talisman for gardeners and agricultural efforts.

Geological facts

Despite its name, moss agate does not contain any organic moss or plant material; the patterns are purely mineral based. It is chemically a variety of chalcedony rather than a true agate because it lacks the typical concentric banding.

Field identification & locations

Identify in the field by its translucent body combined with green filaments (dendrites). Commonly found in India, Brazil, Uruguay, and the United States (specifically the Yellowstone River valley in Montana).