Rock Identifier
Moss Agate (Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)) — mineral
mineral

Moss Agate

Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)

Hardness: 6.5-7 Mohs; Color: Clear to milky white with green, black, or brown inclusions; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (cryptocrystalline); Specific Gravity: 2.58–2.64.

Hardness
6
Color
Clear to milky white with green, black, or brown inclusions
Luster
Vitreous to waxy
Identified More mineral →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Hardness: 6.5-7 Mohs; Color: Clear to milky white with green, black, or brown inclusions; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (cryptocrystalline); Specific Gravity: 2.58–2.64.

Formation & geological history

Formed from the deposition of silica-rich groundwater in cavities of igneous rocks. The 'moss' effect is created by the presence of manganese or iron oxides that grow in dendritic (tree-like) patterns as the silica cools.

Uses & applications

Primarily used in jewelry (cabochons, beads, pendants), ornamental carvings, and as a popular specimen for rock collectors.

Geological facts

Despite its name, Moss Agate does not contain organic matter or real moss; the patterns are strictly mineral-based. It has historically been known as the 'gardener's stone' due to folklore claiming it helped crops grow.

Field identification & locations

Identify by looking for translucent chalcedony containing 'branching' green or dark inclusions that resemble underwater plants. It is commonly found in India, Brazil, Uruguay, central Europe, and the western United States.

More like this

Other mineral specimens

Sandstone (with potential mineral staining/concretions) (Arenite (SiO2 based)) — sedimentary

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

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

Epidote

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

metamorphic
Nephrite Jade (Nephrite) — Mineral/Rock

Nephrite Jade

Nephrite

Mineral/Rock
Banded Gneiss (River Rock/Pebble) (Gneiss (specifically a banded variety often found as a river rock)) — Metamorphic 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

Green Apatite on Albite

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

mineral
Epidote (Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)) — mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral