mineral

Quartz geode/druse, likely chalcedony matrix

Quartz, silicon dioxide (SiO₂), with possible microcrystalline chalcedony

AI-generated identification · may be incorrect

White to gray, translucent quartz crystals with vitreous to sugary drusy luster; Mohs hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The rounded cavities and sparkling crystal coating are characteristic of a geode or vug.

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited quartz and chalcedony in cavities of volcanic or sedimentary host rock, commonly during late-stage hydrothermal alteration. Exact age and locality cannot be determined from the photograph.

Uses & applications

Used as a decorative specimen, lapidary material, and source of quartz for ornaments; attractive druse may be used in jewelry. Common pieces generally have modest commercial value.

Geological facts

The sparkling surface consists of many tiny quartz crystal faces rather than glass. Gray patches may represent chalcedony, clay, or included host minerals.

Field identification & locations

Identify by its cavity lining, glassy sparkle, hardness, and lack of cleavage; quartz will scratch ordinary glass and will not fizz in dilute acid. Common sources include Brazil, Uruguay, Mexico, Morocco, and the western United States.