mineral

Agate

Agate (Silicon Dioxide - SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Multi-colored (this specimen shows translucent honey, orange, and white banding); Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline (Trigonal/Monoclinic); Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Luster: Waxy to vitreous

Identified February 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in microcrystalline layers within the cavities of volcanic rocks (especially basalt) or some sedimentary rocks, where silica-rich groundwater gradually precipitates. Ages vary from Cenozoic to Precambrian depending on the host rock.

Uses & applications

Commonly used in jewelry (cabochons), lapidary art, decorative ornaments, and industrial applications such as precision mortar and pestles due to its hardness and chemical resistance.

Geological facts

Agate is a variety of chalcedony. The name comes from the Achates River in Sicily, where it was first discovered in ancient times. No two agates are exactly alike due to the unique rhythm of mineral deposition.

Field identification & locations

Identify in the field by its characteristic translucency when held to light, waxy texture, conchoidal fracture, and concentric 'iris' or 'landscape' banding. Frequently found in riverbeds, lake shores (like Lake Superior), and volcanic regions.