mineral

Agate

Silicon Dioxide (SiO2) - Banded Chalcedony

AI-generated identification · may be incorrect

Hardness: 6.5–7 on Mohs scale; Color: Pinkish-white with concentric banding; Luster: Waxy to vitreous; Crystal structure: Hexagonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.

Hardness: 6
Color: Pinkish-white with concentric banding
Luster: Waxy to vitreous

Identified April 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities (vesicles) of volcanic rocks or ancient lava flows where silica-rich groundwater percolates and deposits layers of microcrystalline quartz over time.

Uses & applications

Used primarily in jewelry (cabochons), ornamental carvings, as well as industrial laboratory equipment like mortars and pestles due to its hardness and chemical resistance.

Geological facts

Agate is named after the Achates River (now Dirillo River) in Sicily. It is often found as nodules within volcanic host rocks and is known for its incredible variety of patterns and colors.

Field identification & locations

Identify in the field by its characteristic waxy luster and translucent banding when held to light. Common in lake shores (like Lake Superior), riverbeds, and volcanic regions.