mineral

Banded Agate

Agate (Silicon Dioxide - SiO2)

Hardness: 6.5-7 Mohs; Color: Varied (white, gray, translucent); Luster: Vitreous to waxy; Crystal Structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Varied (white, gray, translucent)
Luster: Vitreous to waxy

Identified June 24, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Varied (white, gray, translucent); Luster: Vitreous to waxy; Crystal Structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed as a secondary mineral in volcanic cavities (vesicles) by the slow deposition of silica from groundwater. The bands represent different stages of deposition and impurities.

Uses & applications

Used primarily in jewelry, lapidary arts, decorative beads, and historically for precision instruments like mortar and pestles due to hardness.

Geological facts

Agate is a variety of chalcedony. The bands are caused by variations in the composition of the silica-rich fluids that seep into the rock cavities over thousands of years.

Field identification & locations

Identify by its waxy luster, translucency, and the presence of fine, concentric color bands. It is commonly found in riverbeds and volcanic regions globally (e.g., Brazil, USA, Germany).