mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Gray, brown, and translucent white bands; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Gray, brown, and translucent white bands
Luster: Waxy to vitreous

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in volcanic rock cavities or ancient sedimentary pockets where silica-rich groundwater deposited layers of microcrystalline quartz over thousands of years. Layers represent different periods of mineral deposition.

Uses & applications

Widely used for ornamental jewelry, tumbled gemstones, decorative carvings, and historically for precision bearings/mortars due to high hardness.

Geological facts

Agate was named by the Greek philosopher Theophrastus after the Achates River in Sicily. No two agates are identical, making every specimen unique to its formation environment.

Field identification & locations

Identified by its distinctive concentric or parallel banding and translucency. Commonly found in lake shores (like Lake Superior), riverbeds, and volcanic areas. Look for a waxy texture and light passing through the edges.