mineral

Likely quartz-rich rock fragment

Quartz (SiO₂), possibly in a feldspar-bearing granite or pegmatite matrix

AI-generated identification · may be incorrect

White to translucent, vitreous luster, irregular fracture with some planar faces; quartz hardness is Mohs 7, with no cleavage and a specific gravity near 2.65. The image is insufficient to determine crystal habit or confirm associated minerals.

Identified August 14, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in an igneous vein, pegmatite, or weathered quartz-bearing rock; age depends on its source, commonly Precambrian to Mesozoic. The brown coating may be iron-oxide staining or surface soil.

Uses & applications

Quartz is used in glass, electronics, abrasives, countertops, and specimen collecting; attractive crystals may be cut as gemstones. The pictured fragment has little commercial value unless crystal quality is better than visible.

Geological facts

Quartz commonly shows conchoidal fracture and does not scratch easily with a steel knife. White quartz can resemble calcite, feldspar, or weathered ceramic, so a hardness test is useful.

Field identification & locations

Check whether it scratches glass and whether a steel knife fails to scratch it; quartz will not fizz in dilute acid, unlike calcite. Common sources include hydrothermal veins, pegmatites, granites, and quartz-rich gravels.