mineral

Likely iron-stained quartz or quartzite fragment

Quartz (SiO₂), possibly quartzite; exact identification is uncertain from the image

AI-generated identification · may be incorrect

Tan-brown, opaque to slightly translucent, with a rough, irregular fracture and no obvious cleavage. Quartz has Mohs hardness 7, a trigonal crystal structure, and vitreous luster; the brown color may come from iron-oxide staining.

Identified October 15, 2026More mineral →

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Physical properties

Formation & geological history

Quartz forms in many igneous, sedimentary, and metamorphic settings; quartzite forms when quartz-rich sandstone is metamorphosed. The specimen’s age and specific origin cannot be determined from the photograph.

Uses & applications

Quartz is used in glass, electronics, abrasives, and jewelry; quartzite is used as building stone and aggregate. This small fragment is mainly of interest as a field or teaching specimen.

Geological facts

Quartz is one of Earth’s most abundant minerals. Iron oxides commonly stain quartz and quartzite yellow, tan, or brown.

Field identification & locations

Look for hardness sufficient to scratch glass, lack of cleavage, and a glassy-looking fracture; a closer view or hardness test would help distinguish quartz from quartzite. Quartz occurs worldwide in veins and many rock types.