Rock Identifier
Quartz geode / druzy quartz (Quartz (SiO₂), likely a small chalcedony-lined geode with drusy quartz crystals) — mineral
mineral

Quartz geode / druzy quartz

Quartz (SiO₂), likely a small chalcedony-lined geode with drusy quartz crystals

AI-generated identification · may be incorrect

Typically white to translucent, vitreous crystals lining a hollow cavity; Mohs hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The tan exterior is likely iron-stained host rock or chalcedony.

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Physical properties

Typically white to translucent, vitreous crystals lining a hollow cavity; Mohs hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The tan exterior is likely iron-stained host rock or chalcedony.

Formation & geological history

Forms when silica-rich groundwater deposits chalcedony and quartz crystals inside gas cavities or cavities in volcanic rock; commonly Cenozoic or younger, though exact age cannot be determined from the image.

Uses & applications

Used as decorative stone, mineral specimens, and jewelry components; small common pieces generally have modest value.

Geological facts

The sparkly cavity lining is called druse or druzy quartz. Quartz is one of Earth’s most abundant minerals and often develops six-sided crystal faces when space permits.

Field identification & locations

Common in basaltic volcanic regions and sedimentary limestone cavities, especially Brazil, Uruguay, Mexico, Morocco, and the United States. A glassy luster, hardness resisting steel, and crystal-lined hollow distinguish it from ordinary calcite or slag.