mineral

Quartz crystal fragment

Quartz (silicon dioxide, SiO₂), likely ordinary or smoky quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent tan-brown color, vitreous luster, and conchoidal fracture with indistinct cleavage. The triangular fragment appears naturally fractured or broken from a larger crystal, possibly with inclusions or surface iron staining.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and igneous or metamorphic rocks over a wide range of geological ages. Brown coloration may result from iron oxides or radiation-induced smoky coloration.

Uses & applications

Used extensively in glass, ceramics, abrasives, electronics, and watches; attractive transparent pieces may be cut as gemstones or kept as mineral specimens.

Geological facts

Quartz is one of Earth’s most abundant minerals and has a distinctive hardness that can scratch ordinary window glass. The specimen’s rough, irregular form prevents confident identification of a specific quartz variety from the photograph alone.

Field identification & locations

Identify by its glassy luster, lack of obvious cleavage, hardness, and common hexagonal crystal habit when intact; common sources include Brazil, Madagascar, the United States, and many granitic terrains. A steel knife should not scratch it, while it can scratch glass.