mineral

Rock crystal (clear quartz), likely rough or lightly polished

Quartz — silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Colorless to smoky-clear, vitreous luster, six-sided crystal structure, no true cleavage, conchoidal fracture; Mohs hardness 7 and specific gravity about 2.65. The pictured piece appears translucent with irregular faceted surfaces, though exact identification is limited by the image.

Identified September 21, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and cavities in igneous or metamorphic rocks; crystals may form over broad geological timescales from Precambrian to recent. Its angular shape may reflect natural fracture or human shaping.

Uses & applications

Used for glass, electronics, abrasives, optical components, and specimen collecting; attractive crystals may be used decoratively or in jewelry. This small, cloudy specimen has modest commercial value.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure. It commonly forms the crystal-lined cavities called geodes.

Field identification & locations

Identify by hardness, glassy luster, lack of cleavage, and conchoidal fracture; it should scratch ordinary glass but not be scratched by a steel knife. Common localities include Brazil, Madagascar, Arkansas, the Alps, and many hydrothermal veins.