sedimentary

Brown Agate

Cryptocrystalline Silica (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Brown, tan, and translucent amber; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Brown, tan, and translucent amber
Luster: Waxy to vitreous

Identified June 17, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Brown, tan, and translucent amber; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64.

Formation & geological history

Agate forms as a secondary mineral in nodules within volcanic rocks or ancient sedimentary cavities. Silicon dioxide precipitates from groundwater into voids, often forming concentric bands over thousands of years.

Uses & applications

Commonly used for lapidary arts, jewelry (cabochons), burnishing tools, decorative carvings, and as a healing stone in metaphysical practices.

Geological facts

Agate was named by Theophrastus, a Greek philosopher, who discovered the stone along the shoreline of the river Achates in Sicily. No two agates are exactly alike due to the unique mineral impurities present during formation.

Field identification & locations

Identify in the field by its translucent edges when held to light, its waxy texture, and conchoidal (shell-like) fracture. Commonly found in riverbeds, glacial tills, and volcanic regions globally.