Rock Identifier

gemstone

Agate

Silicon Dioxide (Chalcedony), SiO2

AI-generated identification · may be incorrect

Hardness: 6.5-7 on the Mohs scale; Color: Variable, often white, gray, red, brown, or multicolored with banded patterns; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline quartz); Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Luster: Waxy to vitreous

Identified August 7, 2026More gemstone →

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Physical properties

Hardness: 6.5-7 on the Mohs scale; Color: Variable, often white, gray, red, brown, or multicolored with banded patterns; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline quartz); Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed primarily within cavities of volcanic and metamorphic rocks through the deposition of silica-rich groundwater solutions in concentric layers over long geological periods.

Uses & applications

Used widely in ornamental objects, jewelry, carvings, and as industrial bearings or mortars due to its hardness.

Geological facts

Agate was named by Theophrastus, a Greek philosopher and naturalist, who discovered the stone along the shoreline of the Achates River in Sicily.

Field identification & locations

Easily identified by its characteristic colorful bands and waxy luster. Commonly found in regions with past volcanic activity worldwide.

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