metamorphic
Quartzite Pebble
Metamorphic Quartzite (SiO2)
Hardness: 7 (Mohs scale); Color: Tan/brown/buff; Luster: Sub-vitreous to dull (weathered); Crystal structure: Hexagonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65
- Hardness
- 7 (Mohs scale)
- Color
- Tan/brown/buff
- Luster
- Sub-vitreous to dull (weathered)
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Physical properties
Hardness: 7 (Mohs scale); Color: Tan/brown/buff; Luster: Sub-vitreous to dull (weathered); Crystal structure: Hexagonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events. This specimen has been rounded by fluvial or glacial erosion.
Uses & applications
Primarily used in construction (railway ballast, crushed stone), glass manufacturing, and as decorative landscaping stones.
Geological facts
Quartzite is so tough that it often survives the complete erosion of the original mountain range it formed in, ending up as pebbles in distant riverbeds. It is harder than steel and can scratch glass easily.
Field identification & locations
Identify in the field by its extreme hardness and smooth, water-worn texture. Common in riverbeds and glacial tills across North America and Europe. Collectors look for unique colors or internal banding.
