mineral

Banded Agate

Silicon Dioxide (SiO2) - Variety Agate

Hardness: 6.5-7 Mohs; Color: Gray, white, and yellow banding; Luster: Waxy to vitreous; Crystal Structure: Hexagonal (cryptocrystalline); Cleavage: None; Fracture: Conchoidal.

Hardness: 6
Color: Gray, white, and yellow banding
Luster: Waxy to vitreous

Identified July 16, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Gray, white, and yellow banding; Luster: Waxy to vitreous; Crystal Structure: Hexagonal (cryptocrystalline); Cleavage: None; Fracture: Conchoidal.

Formation & geological history

Formed in volcanic or metamorphic rocks, typically filling cavities or veins. These bands occur through the rhythmic deposition of silica from groundwater over long periods.

Uses & applications

Commonly used in jewelry (cabochons, beads), decorative objects, and historically for making mortars and pestles due to its hardness and resistance to chemicals.

Geological facts

Agate is named after the Achates River in Sicily where it was first discovered. The distinct banding is caused by variations in the mineral and impurity content during the slow growth process.

Field identification & locations

Identify in the field by its waxy luster, conchoidal fracture, and characteristic banding. Often found as nodules in gravel beds or volcanic regions like Brazil, India, and the United States (Lake Superior region).