metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Pure white to light grey; Luster: Dull to vitreous; Crystal Structure: Trigonal/Hexagonal crystals within a granular mass; Cleavage: None; Specific Gravity: 2.63 - 2.65
- Hardness
- 7 on Mohs scale
- Color
- Pure white to light grey
- Luster
- Dull to vitreous
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Physical properties
Hardness: 7 on Mohs scale; Color: Pure white to light grey; Luster: Dull to vitreous; Crystal Structure: Trigonal/Hexagonal crystals within a granular mass; Cleavage: None; Specific Gravity: 2.63 - 2.65
Formation & geological history
Formed through the regional or contact metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize the quartz grains, locking them together in a tight mosaic. These pebbles are rounded by high-energy water environments like beaches or riverbeds.
Uses & applications
Used as decorative landscaping stones, aquarium gravel, high-purity silica for the glass industry, and as a durable construction aggregate.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rock layers, leading to the formation of ridges. This specific pebble is a 'beach cobble' shaped by thousands of years of wave action.
Field identification & locations
Identify in the field by its inability to be scratched by a steel knife and its granular, sugary texture. Common in glacial deposits and high-energy coastal zones. Look for a sparking 'sugary' appearance under direct light.
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