mineral

Chalcedony (likely common agate)

Microcrystalline quartz, SiO₂; chalcedony variety, possibly agate

AI-generated identification · may be incorrect

Translucent gray-white with brown iron-oxide staining and a waxy to vitreous luster; quartz crystal structure, Mohs hardness 6.5–7, no cleavage, conchoidal fracture. Specific gravity is about 2.6.

Identified October 15, 2026More mineral →

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Physical properties

Translucent gray-white with brown iron-oxide staining and a waxy to vitreous luster; quartz crystal structure, Mohs hardness 6.5–7, no cleavage, conchoidal fracture. Specific gravity is about 2.6.

Formation & geological history

Silica-rich fluids deposited quartz in cavities or fractures, later forming microcrystalline chalcedony; such deposits occur in many geological ages and settings.

Uses & applications

Used for beads, cabochons, carvings, and ornamental objects; it is also collected as a common silica specimen.

Geological facts

Agate is distinguished from plain chalcedony by visible curved or parallel bands; none are obvious here, so the specific variety is uncertain.

Field identification & locations

Look for its glassy-waxy surface, translucency, and curved shell-like fracture; common in volcanic rocks, veins, and stream gravels worldwide. This appears to be a rough fragment, possibly naturally fractured.