Mineral

Moss Agate

Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)

Hardness: 6.5–7 on Mohs scale; Color: Clear to milky white base with green or brown dendritic patterns; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Specific Gravity: 2.58–2.64.

Hardness: 6
Luster: Vitreous to waxy

Identified April 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the deposition of silica-rich groundwater in cavities of igneous rocks. The 'moss' patterns are caused by impurities of manganese or iron oxides that form dendritic patterns during crystallization.

Uses & applications

Primarily used in jewelry (cabochons), lapidary carvings, and as a collector's specimen. It is also popular in holistic and metaphysical communities.

Geological facts

Despite its name, moss agate does not contain organic plant matter; the 'moss' is purely mineral growth. It is often called the 'Mocha Stone' after the city of Mocha in Yemen, an early trade source.

Field identification & locations

Identify by its translucent body combined with branching, moss-like inclusions. It is commonly found in India, Brazil, Uruguay, and the United States (notably Montana). For collectors, look for high transparency and vibrant green 'moss'.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral