mineral

Banded Agate

Cryptocrystalline Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Multi-colored bands (brown, white, grey, beige); Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.58-2.64

Hardness: 6
Color: Multi-colored bands (brown, white, grey, beige)
Luster: Waxy to vitreous

Identified May 9, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Multi-colored bands (brown, white, grey, beige); Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.58-2.64

Formation & geological history

Formed primarily in volcanic or metamorphic environments when silica-rich groundwater fills gas cavities (vesicles) in igneous rocks. The bands represent different pulses of silica deposition over thousands of years.

Uses & applications

Commonly used in jewelry (cabochons, beads), decorative carvings, precision balances, and as a collectible gemstone for lapidary work.

Geological facts

Agate is named after the Achates River in Sicily. No two agates are exactly alike due to the unique chemical conditions during the formation of each band.

Field identification & locations

Identify in the field by its translucent properties when held to light, conchoidal fracture, and distinct parallel banding. Frequently found in riverbeds, beaches, and volcanic ash deposits.