mineral

Agate

SiO2 (Silicon dioxide, cryptocrystalline quartz)

Hardness: 6.5-7, Color: Gray, white, translucent with varied inclusions (possibly an ocean agate or similar variety), Luster: Vitreous, Crystal structure: Trigonal (microcrystalline), Cleavage: None

Hardness: 6

Identified June 18, 2026More mineral →

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Physical properties

Hardness: 6.5-7, Color: Gray, white, translucent with varied inclusions (possibly an ocean agate or similar variety), Luster: Vitreous, Crystal structure: Trigonal (microcrystalline), Cleavage: None

Formation & geological history

Forms in cavities of volcanic rocks or ancient lavas, where silica-rich waters deposit microcrystalline quartz in concentric layers.

Uses & applications

Lapidary art, jewelry, ornamental carvings, collecting.

Geological facts

Agate is a diverse type of chalcedony characterized by its fineness of grain and brightness of color. It is named after the Achates River in Sicily where it was first found.

Field identification & locations

Identifiable by its smooth polish, waxy or vitreous luster, banded or translucent appearance with distinct inclusions. Commonly found worldwide in areas with past volcanic activity.

Other mineral specimens

See all

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