sedimentary

Banded Agate (Tumbled)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Variegated bands of pink, white, gray, and brown; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Cleavage: None; SG: 2.58-2.64.

Hardness: 6
Color: Variegated bands of pink, white, gray, and brown
Luster: Vitreous to waxy

Identified July 13, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Variegated bands of pink, white, gray, and brown; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Cleavage: None; SG: 2.58-2.64.

Formation & geological history

Formed as a secondary mineral in volcanic rock cavities (vesicles) or sedimentary fissures. Silicate-rich groundwater deposits layers of rhythmic crystallization over thousands of years.

Uses & applications

Used primarily in jewelry (beads, cabochons), ornamental decoration, holistic healing practices, and industrial use in precision mortars and pestles.

Geological facts

Agate is named after the Achates River (now the Dirillo) in Sicily. The distinct banding is caused by variations in the impurity concentration during the wall-inward growth process.

Field identification & locations

Identified by its waxy luster and unique parallel banding. Tumbled specimens feel very smooth and are significantly harder than glass. Common in Brazil, India, and the Lake Superior region.