mineral
Iron-Stained Quartz
Silicon Dioxide (SiO2) with Iron Oxide/Limonite coating
Hardness of 7 on the Mohs scale, translucent to transparent clarity with cloudy patches, vitreous to greasy luster, hexagonal crystal system (massive habit in this specimen), conchoidal fracture, and specific gravity around 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, translucent to transparent clarity with cloudy patches, vitreous to greasy luster, hexagonal crystal system (massive habit in this specimen), conchoidal fracture, and specific gravity around 2.65.
Formation & geological history
Formed in hydrothermal veins or pegmatites where silica-rich fluids cooled and crystallized over millions of years. The yellow-to-orange staining is due to secondary weathering and infiltration by iron oxides (limonite/hematite).
Uses & applications
Used in decorative tumbling, lapidary arts, mineral collecting, and as a raw material for silicon extraction.
Geological facts
Quartz is one of the most abundant minerals on Earth's continental crust. Specimens with iron oxide staining are extremely common and often found in weathered surface soils or river gravels.
Field identification & locations
Easily identified by its hardness (scratches glass), lack of cleavage, and characteristic rusty orange-yellow iron staining on the surface. Found globally in almost any geological environment.
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