metamorphic
Grey Quartzite Pebble
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Grey with white striations; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Grey with white striations
- Luster
- Vitreous to dull
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: Grey with white striations; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, causing the original quartz grains to recrystallize into a dense interlocking mosaic. Common throughout almost all geological ages.
Uses & applications
Used in construction as crushed stone or road ballast, as a refractive material in high-temperate industrial processes, and occasionally for decorative landscaping or lapidary tumbling.
Geological facts
Quartzite is so hard that it will scratch glass and even steel. It is one of the most durable rocks on Earth, often forming the resistant 'backbone' of mountain ranges that survives erosion longer than surrounding rock types.
Field identification & locations
Identify in the field by its extreme hardness (cannot be scratched by a knife) and sugary/granular texture on broken surfaces. Found in riverbeds, glacial deposits, and mountain outcrops globally.
More like this
