mineral

Agate (Carnelian / Chalcedony)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Honey-yellow, translucent brown to orange; Luster: Waxy to vitreous; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

Hardness: 6
Color: Honey-yellow, translucent brown to orange
Luster: Waxy to vitreous

Identified July 23, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Honey-yellow, translucent brown to orange; Luster: Waxy to vitreous; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

Formation & geological history

Forms primarily within cavities (geodes) of volcanic igneous rocks or sedimentary formations as silica-rich water precipitates layer by layer over time.

Uses & applications

Popular for gemstone lapidary work, tumbling, jewelry making, ornamental carvings, and rock collecting.

Geological facts

Agates are microcrystalline varieties of quartz. The translucent honey-yellow to orange coloration is typically due to iron oxide impurities embedded within the silica matrix.

Field identification & locations

Look for a waxy, smooth texture, conchoidal fracture surfaces, high translucency under light, and a high hardness that scratches glass. Commonly found along gravel bars, riverbeds, and volcanic rock outcrops worldwide.