mineral

Agate

Chalcedony SiO2

Hardness: 6.5-7, Color: Gray, white, translucent, Luster: Vitreous, Crystal structure: Cryptocrystalline, Cleavage: None, Specific gravity: 2.58-2.64. Features concentric banding.

Hardness: 6

Identified July 17, 2026More mineral →

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Physical properties

Hardness: 6.5-7, Color: Gray, white, translucent, Luster: Vitreous, Crystal structure: Cryptocrystalline, Cleavage: None, Specific gravity: 2.58-2.64. Features concentric banding.

Formation & geological history

Forms in vesicles of volcanic rocks or within sedimentary rocks from silica-rich groundwater. Often forms over millions of years.

Uses & applications

Used extensively in jewelry creation (such as this cabochon pendant), carving, lapidary arts, and collecting.

Geological facts

Agate is named after the Achates River in Sicily where it was discovered. The banding is caused by periodic variations in silica deposition.

Field identification & locations

Identified by concentric banding and translucency. Found worldwide, with notable deposits in Brazil, Uruguay, and the USA. This particular specimen is shaped and drilled for use as a jewelry pendant.