mineral

Quartz geode or drusy quartz cluster

Quartz (silicon dioxide, SiO₂), likely microcrystalline quartz lining a cavity

AI-generated identification · may be incorrect

White to pale translucent crystals with a glassy to sugary luster and irregular botryoidal exterior; quartz has Mohs hardness 7, no cleavage, conchoidal fracture, hexagonal crystal structure, and specific gravity about 2.65.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater deposited quartz crystals inside a vesicle or cavity in volcanic rock, commonly during the Cenozoic or older. The specimen appears cut or broken open to expose the crystalline interior.

Uses & applications

Used as a decorative mineral specimen, jewelry component, and lapidary material; quartz is also important industrially in glass, electronics, abrasives, and engineered stone.

Geological facts

The sparkling surface is called drusy or druzy quartz, consisting of many tiny crystals. Quartz can be distinguished from calcite because it is much harder and does not readily react with dilute hydrochloric acid.

Field identification & locations

Common in geodes from Brazil, Uruguay, Mexico, Morocco, and the western United States. Field identification: glassy luster, visible crystal facets, hardness sufficient to scratch ordinary glass, and lack of cleavage.