mineral

Green Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Hardness: 6.5-7 Mohs; Color: Various shades of green with translucent banding; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Various shades of green with translucent banding
Luster: Waxy to vitreous

Identified June 22, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in volcanic and metamorphic rocks when silica-rich groundwater fills cavities (vugs). Often associated with ancient basaltic lava flows.

Uses & applications

Widely used in jewelry (beads, cabochons), ornamental carvings, stone seals, and as tumbled decorative stones in the holistic and collecting communities.

Geological facts

The name 'Agate' comes from the Achates River in Sicily. While natural green agate exists due to chromium or nickel, many bright green specimens on the market are dyed to enhance their color and banding.

Field identification & locations

Identify in the field by its characteristic concentric layering or banding, waxy texture, and lack of cleavage. Often found in riverbeds or coastal areas where volcanic rocks have eroded.

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