metamorphic
Yellow Quartzite (River Pebble)
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Yellow-orange to tan due to iron oxide staining; Luster: Greasy to vitreous when wet, dull when dry; Structure: Crystalline but appears granular; Cleavage: None (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- Yellow-orange to tan due to iron oxide staining
- Luster
- Greasy to vitreous when wet, dull when dry
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: Yellow-orange to tan due to iron oxide staining; Luster: Greasy to vitreous when wet, dull when dry; Structure: Crystalline but appears granular; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, often recycled as a river pebble through erosion and transport in alluvial environments.
Uses & applications
Used in landscaping, as a construction aggregate, for road ballast, and sometimes as a minor decorative stone in rock gardens or terrariums.
Geological facts
Quartzite is so tough that it often breaks through the sand grains rather than around them. The yellow tint is usually a result of limonite or other iron-bearing minerals staining the surface.
Field identification & locations
Identify by its ability to scratch glass and its lack of reaction to acid. Commonly found in riverbeds, glacial tills, and mountainous regions where ancient sedimentary sequences have been metamorphosed.
