metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: light gray to white; Luster: vitreous to dull; Crystal structure: hexagonal (trigonal); Grainy, sand-like texture with smooth water-worn surface; Specific gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- Color
- light gray to white
- Luster
- vitreous to dull
Identified More metamorphic →
Explore Quartzite Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: light gray to white; Luster: vitreous to dull; Crystal structure: hexagonal (trigonal); Grainy, sand-like texture with smooth water-worn surface; Specific gravity: 2.6-2.7.
Formation & geological history
Formed when quartz-rich sandstone is subjected to heat, pressure, and chemical activity of metamorphism. This specific specimen has been further shaped by river or coastal erosion (rounding) during the Quaternary period.
Uses & applications
Used as decorative garden stone, in construction aggregates, and historically as a tool stone due to its extreme hardness and durability.
Geological facts
Quartzite is so hard that it will scratch glass and even high-quality steel. It is more resistant to weathering than the sandstone from which it originated.
Field identification & locations
Identified in the field by its hardness (cannot be scratched by a knife) and its grainy 'sugary' appearance under a lens. Common in glacial till and riverbeds worldwide.
More like this
