metamorphic

Iron-stained quartz-rich rock, possibly limonite-bearing quartzite

Quartz (SiO₂) with iron oxides/hydroxides, chiefly hematite and goethite

AI-generated identification · may be incorrect

Likely mostly quartz with rusty orange-brown iron staining; glassy to dull luster, granular texture, no obvious cleavage, and approximate Mohs hardness 6–7. The small rounded fragment appears pale gray, tan, and orange-brown.

Identified September 6, 2026More metamorphic →

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Physical properties

Formation & geological history

Probably formed from silica-rich sediment or vein material, later cemented or metamorphosed, with secondary oxidation of iron-bearing minerals near the surface. Exact geological age and locality cannot be determined from the photograph.

Uses & applications

Common quartz-rich material has little commercial value as a fragment, though quartzite is used as aggregate, building stone, and decorative stone; attractive pieces may be collected.

Geological facts

Iron oxides commonly produce vivid rust-orange coatings and patches on otherwise gray or white quartz-rich rocks.

Field identification & locations

Test suspected quartz by scratching glass; it should scratch it, while a steel knife generally does not. Common in quartz veins, weathered outcrops, stream gravels, and iron-rich soils.