metamorphic
Quartzite with Quartz Vein
Metamorphosed sandstone (SiO2)
Hardness: 7 on Mohs scale; Color: Grayish-brown matrix with a milky white vein; Luster: Vitreous to dull; Crystal structure: Hexagonal (within vein); Cleavage: None (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- Grayish-brown matrix with a milky white vein
- 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: Grayish-brown matrix with a milky white vein; Luster: Vitreous to dull; Crystal structure: Hexagonal (within vein); Cleavage: None (conchoidal fracture).
Formation & geological history
Formed when quartz-rich sandstone is subjected to high heat and pressure, causing the sand grains to recrystallize. The white vein formed later from silica-rich hydrothermal fluids filling a fracture.
Uses & applications
Used as decorative stone, crushed stone for road construction, and ballast. High-purity quartzite is used to produce ferrosilicon and industrial silica sand.
Geological facts
Quartzite is so tough that it often survives intense weathering and transport in rivers better than most other rocks, leading to the rounded 'river rock' shape seen here.
Field identification & locations
Identify by its extreme hardness (it will scratch glass) and its sugary texture that sparkles in the sun. Found globally in ancient mountain belts and river beds draining from them.
More like this
