gemstone

Banded Agate

Cryptocrystalline Silicon Dioxide (SiO2)

Hardness: 6.5–7 (Mohs scale), Color: Translucent gray and white bands, Luster: Vitreous/Waxy, Structure: Cryptocrystalline Quartz, Cleavage: None, Specific Gravity: 2.58–2.64

Hardness: 6

Identified July 18, 2026More gemstone →

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Physical properties

Hardness: 6.5–7 (Mohs scale), Color: Translucent gray and white bands, Luster: Vitreous/Waxy, Structure: Cryptocrystalline Quartz, Cleavage: None, Specific Gravity: 2.58–2.64

Formation & geological history

Formed primarily in volcanic rock cavities or sedimentary geodes through the deposition of silica from groundwater into concentric layers over thousands of years.

Uses & applications

Used extensively in jewelry, lapidary arts, decorative ornaments, and historically for burnishing tools and mortars/pestles due to its hardness.

Geological facts

The unique banding is caused by rhythmic crystallization of silica; no two agates are exactly alike. They have been used as amulets and ornaments since the era of ancient Babylon.

Field identification & locations

Identified by concentric rhythmic banding and translucency. Commonly found in Brazil, Uruguay, and various riverbeds or volcanic regions worldwide. Collectors look for clarity and sharp band contrast.

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