mineral

Quartz geode (likely druzy quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Colorless to milky-white, translucent crystals with vitreous luster; hexagonal crystal structure, conchoidal fracture, no cleavage, Mohs hardness 7, and specific gravity about 2.65. The rough exterior and sparkling crystal-lined cavity are characteristic of a geode.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited quartz crystals in a gas cavity or vug within volcanic rock, commonly basalt. Geodes formed over long periods, generally from the Cenozoic to older volcanic episodes, but the exact age cannot be determined from the image.

Uses & applications

Used as a display and lapidary specimen; quartz is important in glassmaking, electronics, abrasives, and engineered stone. Druzy quartz is occasionally used in jewelry and décor.

Geological facts

The crystals likely grew inward from the cavity walls, producing a sparkling druzy texture. A UV reaction is not expected for ordinary quartz, though impurities can create weak fluorescence.

Field identification & locations

Identify by its hollow or vuggy form, glittering quartz crystals, hardness, and lack of cleavage; it scratches glass but not readily with a steel knife. Common sources include Brazil, Uruguay, Mexico, Morocco, and the United States.