mineral

Agate

Silicon Dioxide (Quartz), SiO2

Hardness: 6.5-7 on the Mohs scale, Color: Various shades of brown, white, and translucent, Luster: Vitreous to waxy, Crystal structure: Trigonal (microcrystalline quartz/chalcedony), Cleavage: None

Hardness: 6

Identified July 29, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on the Mohs scale, Color: Various shades of brown, white, and translucent, Luster: Vitreous to waxy, Crystal structure: Trigonal (microcrystalline quartz/chalcedony), Cleavage: None

Formation & geological history

Formed by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, often occurring over millions of years.

Uses & applications

Used primarily in jewelry, decorative items, ornamental carvings, and lapidary art.

Geological facts

Agates are often found in ancient volcanic lava flows where gas bubbles once formed cavities that later filled with silica-rich water.

Field identification & locations

Can be identified in the field by its waxy luster, microcrystalline structure, and characteristic banding or translucency. Found worldwide, especially in Brazil, India, Madagascar, and the US.