mineral

Agate Slice (Carnelian Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5-7 on Mohs scale; Color: Orange, amber, translucent yellowish-red with concentric color banding; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: ~2.58-2.64.

Hardness: 6
Luster: Waxy to vitreous

Identified July 27, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids precipitate in cavities (vesicles) within volcanic rocks or sedimentary strata over extensive time periods, depositing successive layers of microcrystalline quartz.

Uses & applications

Widely used for ornamental slices, coasters, jewelry cabochons, lapidary art, paperweights, and metaphysical or gemstone collecting.

Geological facts

Agates derive their name from the Achates River (now the Dirillo River) in Sicily, where they were discovered in ancient times. The distinct bands represent different periods of mineral deposition with varying trace elements.

Field identification & locations

Identified by distinct concentric or parallel banding, waxy luster, and high translucency when held up to a light source. Commonly found in Brazil, Uruguay, Madagascar, India, and the Lake Superior region of the USA.

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