metamorphic
Quartzite
Metamorphosed Quartz Sandstone (primarily SiO2)
Hardness: 7 on Mohs scale; Color: typically white to gray, occasionally pink or reddish; Luster: vitreous to dull; Crystal structure: hexagonal (microcrystalline); Cleavage: none (fractures conchoidally); Specific gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- typically white to gray, occasionally pink or reddish
- 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: typically white to gray, occasionally pink or reddish; Luster: vitreous to dull; Crystal structure: hexagonal (microcrystalline); Cleavage: none (fractures conchoidally); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events (orogeny). These rocks can date from the Precambrian to recent geological eras.
Uses & applications
Extensively used as crushed stone in road construction, railway ballast, and as a decorative building stone. High-purity quartzite is used in the manufacture of glass, silicon metal, and ferrosilicon.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the resistive ridges and peaks in mountain ranges. It is significantly harder than the sandstone it originates from because the quartz grains have recrystallized and fused together.
Field identification & locations
Identify in the field by its extreme hardness (it will easily scratch glass and stainless steel) and its granular, sugary texture. Unlike marble, it will not react with dilute acid. It is commonly found in ancient mountain belts and glaciated regions.
More like this
