mineral

Agate (Carnelian type)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, tan, with banding; Luster: Waxy to vitreous; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Hardness: 6
Color: Orange, reddish-brown, tan, with banding
Luster: Waxy to vitreous

Identified July 7, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic rock cavities or sedimentary environments through the deposition of silica from groundwater; often associated with basalt flows.

Uses & applications

Used primarily in lapidary arts for jewelry, decorative carvings, and as a collectible specimen.

Geological facts

The banding in agates is caused by periodic changes in the composition or pressure of the silica-rich fluids during formation. This specimen shows a waxy exterior common to river-worn or weathered nodules.

Field identification & locations

Identify in the field by its translucent edges, waxy luster when broken, and characteristic banding. Commonly found in riverbeds, gravel pits, and volcanic regions.