metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Tan to light grey; Luster: Dull to waxy; Texture: Fine-grained to sugary; Cleavage: None; Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Tan to light grey
- Luster
- Dull to waxy
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: Tan to light grey; Luster: Dull to waxy; Texture: Fine-grained to sugary; Cleavage: None; Specific Gravity: 2.6-2.7
Formation & geological history
Formed from the metamorphism of quartz sandstone under high heat and pressure, causing recrystallization of quartz grains. These rounded pebbles are typically shaped by water erosion in riverbeds or coastal environments.
Uses & applications
Used in construction as crushed stone, in landscaping, and sometimes as a flux in steel making. Very smooth specimens are used as massage stones or decorative accents.
Geological facts
Quartzite is harder than the sandstone it originates from and will scratch glass. It is one of the most durable and resistant rocks on the Earth's surface.
Field identification & locations
Identify by its hardness (cannot be scratched by a steel blade) and sugary texture. Found globally in ancient mountain belts and river deposits.
