metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Pinkish-tan with darker inclusions; Luster: Dull to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.63 - 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Pinkish-tan with darker inclusions
- Luster
- Dull to vitreous
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Pinkish-tan with darker inclusions; Luster: Dull to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.63 - 2.65.
Formation & geological history
Formed from the metamorphism of quartz sandstone under intense heat and pressure. This specific specimen has been rounded into a pebble via water erosion in a river or coastal environment.
Uses & applications
Used as decorative garden stone, railway ballast, and occasionally as a raw material for high-purity silica in glass making. Water-worn pebbles are popular for landscaping.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the crests of mountain ranges. It is tougher than the sandstone from which it originated because the quartz grains have recrystallized and fused together.
Field identification & locations
Identify in the field by its extreme hardness (cannot be scratched by steel) and lack of reaction to acid. It is commonly found in glacial till, riverbeds, and coastal beaches.
More like this
