mineral

Quartz geode

Quartz (SiO₂), likely a quartz-lined geode with a chalcedony rind

AI-generated identification · may be incorrect

White to translucent, glassy-to-dull crystals lining a hollow cavity; quartz hardness 7 Mohs, trigonal crystal system, no cleavage, specific gravity about 2.65. The visible crystals appear chunky and may include milky quartz.

Identified October 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms when mineral-rich water deposits silica inside a cavity in volcanic rock or sediment; the outer rind commonly develops before quartz crystals grow inward. Geode formation spans many geological ages and cannot be dated from the photo.

Uses & applications

Collected as a display specimen; cut geodes are also used for décor and jewelry components.

Geological facts

Geodes may look plain from the outside yet contain crystal-lined cavities; this specimen appears opened or broken to reveal its interior.

Field identification & locations

Quartz geodes are common in volcanic and sedimentary regions, including parts of Brazil, Uruguay, and the western United States. Confirm quartz by its hardness and glassy fracture; image alone cannot establish the exact locality or whether all crystals are quartz.