mineral

Agate

Silicon Dioxide (SiO2)

Hardness of 6.5-7 on the Mohs scale, colors vary from translucent white to brown, red, gray, pink, and blue, waxy to vitreous luster, microcrystalline quartz structure with no distinct cleavage, specific gravity of 2.58-2.64.

Identified July 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily within cavities of volcanic and metamorphic rocks through the deposition of silica from groundwater solutions, often in concentric bands.

Uses & applications

Used in making jewelry, ornamental carvings, polished display specimens, mortar and pestle sets, and industrial knife-edge bearings.

Geological facts

Agate is a diverse variety of chalcedony and has been used since antiquity for ornaments and gemstones, with notable ancient Greek and Roman intaglio rings.

Field identification & locations

Identified by its waxy luster, conchoidal fracture, and characteristic banding patterns; commonly found in riverbeds, volcanic regions, and gravel deposits worldwide.