mineral

Banded Chalcedony (Agate)

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Waxy white to cream. Luster: Waxy to vitreous. Crystal structure: Trigonal (microscopic). Cleavage: None (conchoidal fracture). Specific gravity: 2.60-2.64.

Hardness: 6
Color: Waxy white to cream
Luster: Waxy to vitreous

Identified June 20, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Waxy white to cream. Luster: Waxy to vitreous. Crystal structure: Trigonal (microscopic). Cleavage: None (conchoidal fracture). Specific gravity: 2.60-2.64.

Formation & geological history

Formed primarily through the deposition of silica from groundwater in the cavities of igneous rocks or through sedimentary processes. The banding occurs due to rhythmic crystallization or changes in the chemical composition of the silica-rich fluids.

Uses & applications

Commonly used as gemstones, in jewelry (beads, cabochons), ornamental carvings, and industrially for precision bearings and mortars/pestles due to its hardness and resistance to chemical wear.

Geological facts

The name 'Agate' comes from the Achates River in Sicily, now known as the Dirillo River, where these stones were first found in ancient times. Agate was used as a gemstone by the Ancient Egyptians more than 3,000 years ago.

Field identification & locations

Identified in the field by its distinct waxy luster, conchoidal fracture (smooth, curved breaks), and characteristic banding. Often found as nodules in volcanic landscapes or as pebbles in riverbeds.

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