metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Reddish-brown to tan; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (microcrystalline); Cleavage: None; SG: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Reddish-brown to tan
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Reddish-brown to tan; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (microcrystalline); Cleavage: None; SG: 2.65
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, causing recrystallization of quartz grains. These pebbles are often rounded by water transport in riverbeds or coastal environments.
Uses & applications
Used as decorative stone in landscaping, aggregate in road construction, and occasionally for lapidary work or polishing for collectors.
Geological facts
Quartzite is so tough that it usually breaks through the quartz grains rather than around them, unlike its parent stone, sandstone. This specific pebble shows a smooth, water-worn texture.
Field identification & locations
Identify in the field by its hardness (will scratch glass) and lack of reaction to acid. Commonly found in areas with ancient metamorphic bedrock or as glacial/river till.
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