Moss Agate

Physical Properties

Hardness: 6.5-7 on Mohs scale; Color: Translucent white or gray with green, brown, or red dendritic inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64

Formation & Geological History

Formed through the deposition of silica from groundwater into cavities in igneous rocks. The 'moss' patterns are formed by the presence of manganese and iron oxides during the crystallization process. It can be found in volcanic regions of all geological ages.

Uses & Applications

Primary use is in jewelry (cabochons, beads, pendants), ornamental carvings, and as a popular specimen for gemstone collectors.

Geological Facts

Despite its name, moss agate does not contain organic matter; the plant-like moss patterns are actually inorganic mineral dendrites. In ancient times, it was believed to be a stone of agriculture that helped crops grow.

Field Identification & Locations

Identify by its translucent body combined with branching, moss-like inclusions. Commonly found in India, Brazil, Uruguay, and the western United States. It is often found in riverbeds as water-worn pebbles.

Identified on: 5/20/2026

Mode: Standard