mineral
Quartz (Iron-stained River Pebble)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale. Color: Translucent grey-brown with reddish-orange iron oxide staining. Luster: Vitreous to greasy. Crystal System: Trigonal (microcrystalline/massive). Cleavage: None, conchoidal fracture.
- Hardness
- 7 on Mohs scale
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 7 on Mohs scale. Color: Translucent grey-brown with reddish-orange iron oxide staining. Luster: Vitreous to greasy. Crystal System: Trigonal (microcrystalline/massive). Cleavage: None, conchoidal fracture.
Formation & geological history
Formed via hydrothermal activity or igneous/metamorphic processes, followed by weathering and erosion. The rounded shape indicates water transport in a riverbed or shoreline, causing mechanical tumbling.
Uses & applications
Commonly collected as river rocks, used in decorative landscaping, lapidary tumbling, and basic mineral collections.
Geological facts
Quartz is the second most abundant mineral in the Earth's continental crust. Iron oxide impurities often seep into micro-fractures, giving clear or white quartz a reddish or brownish tint.
Field identification & locations
Field identification: Scratch test (scratches glass and steel), lacks cleavage, displays a waxy to glass-like luster when water-worn. Found globally along stream beds, gravel bars, and beaches.
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