mineral

Polished agate slice

Chalcedony (microcrystalline quartz, SiO₂), likely a pale pink agate geode slice

AI-generated identification · may be incorrect

Translucent pink center with a gray-white banded rim and glossy polished surface. Quartz hardness is 6.5–7 Mohs; trigonal crystal structure at the microscopic level, with no prominent cleavage and conchoidal fracture; specific gravity about 2.6.

Identified October 2, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited successive chalcedony layers in a cavity in volcanic rock, later filled or partly filled with crystals. Agate formation spans many geological ages; the specimen’s age and exact locality cannot be determined from the image.

Uses & applications

Used for jewelry, ornaments, bookends, and decorative polished slices; agate is also used for precision tools and abrasives.

Geological facts

Agate’s fine layers form when silica precipitates in repeated episodes, creating distinctive bands that may be subtle or vivid.

Field identification & locations

Look for waxy-to-glassy luster, translucency, and curved or concentric bands; this piece appears cut and polished, so its natural outer edge is preserved. Agates occur worldwide, especially in volcanic regions.