mineral

Quartz-rich geode or drusy quartz specimen

Quartz, silicon dioxide (SiO₂), likely coating a carbonate or volcanic-rock cavity

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to gray, translucent quartz with glassy to sparkling drusy luster and irregular microcrystals. Quartz is trigonal, lacks cleavage, and has specific gravity about 2.65; the brown material may be iron staining or matrix rock.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater deposited quartz crystals inside a cavity or vug, possibly in volcanic rock or limestone. The exact geological age cannot be determined from the photograph and depends on its locality.

Uses & applications

Used as a decorative and lapidary specimen; attractive drusy surfaces are sold for display, jewelry, and cabochons. It has little industrial value as an isolated specimen.

Geological facts

The glittering surface consists of many tiny quartz crystals rather than metallic glitter. White, chalky areas may include calcite, feldspar, or weathered host rock, so visual identification alone is not definitive.

Field identification & locations

Commonly found in Brazil, Uruguay, Mexico, Morocco, and the western United States. Test with a steel file or glass only cautiously, inspect for hexagonal crystal tips, and use acid testing by an expert if carbonate matrix is suspected.