mineral

Agate

Chalcedony (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Various, often banded; this specimen is grayish/translucent with brownish/reddish iron oxide inclusions, Luster: Waxy to vitreous, Crystal structure: Cryptocrystalline, Cleavage: None, Specific gravity: 2.58-2.64

Hardness: 6
Color: Various, often banded

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in cavities of eruptive rocks or ancient lavas from silica-rich fluids. Can also form in sedimentary environments. Age varies widely depending on the host rock.

Uses & applications

Used in jewelry, lapidary arts, ornaments, and as a collector's stone. Hardness makes it suitable for some industrial uses like precision pendulum bearings or mortar and pestles.

Geological facts

Agate is a variety of chalcedony characterized by its fineness of grain and brightness of color. It is named after the Achates River (now Dirillo) in Sicily, where it was first found.

Field identification & locations

Identified by its waxy luster, translucency, and often banded appearance (though not always prominent). Commonly found worldwide in volcanic areas. For collectors, look for unique patterns and colors. Wetting the stone (as seen in the image) often brings out colors and patterns.