mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5–7 (Mohs). Color: Blue, purple, white, and translucent bands. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Blue, purple, white, and translucent bands
Luster: Vitreous to waxy

Identified May 31, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in volcanic cavities or geodes. As silica-rich groundwater seeps into rock voids, it deposits thin layers of quartz over long periods. Often associated with the Cretaceous or Tertiary volcanic fields.

Uses & applications

Used extensively in jewelry, ornamental carvings, lapidary art, and historically for precision instruments like mortars and pestles due to its hardness. Popular for crystal healing and mineral collections.

Geological facts

The concentric or parallel patterns are called banding and result from the rhythmic crystallization of silica. Famous for its variety, no two agates are exactly alike. This specimen appears to have been cut and polished into a decorative shape.

Field identification & locations

Identified in the field by its translucency, concentric banding, and high hardness (it cannot be scratched by a steel knife). Commonly found in Brazil, Uruguay, and the United States (Lake Superior region and Oregon).