mineral

Quartz geode

Microcrystalline quartz (SiO₂), likely a small druzy quartz geode

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to cream exterior with colorless-to-white sparkling crystals, vitreous luster, and trigonal quartz structure. Quartz lacks cleavage and has conchoidal fracture; the porous appearance may reflect a carbonate or silica-rich outer rind.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-bearing fluids line cavities in volcanic rock or sediment, depositing quartz crystals inward over millions of years. Exact age and host rock cannot be determined from the photograph.

Uses & applications

Used mainly as a decorative or collecting specimen; larger attractive geodes are used in lapidary work and interior décor. This small piece has modest commercial value.

Geological facts

The glittering interior is called druzy or druse quartz, consisting of many tiny crystal faces. A definitive identification would benefit from testing the outer material for fizz with dilute acid and examining a fresh surface.

Field identification & locations

Common in volcanic regions and sedimentary nodules worldwide, including Brazil, Uruguay, Mexico, Morocco, and the western United States. Identify by its hollow or vuggy cavity, sparkling quartz coating, glassy luster, and scratch resistance against ordinary glass.