metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Tan, yellow, or off-white; Luster: Vitreous to dull; Crystal Structure: Hexagonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- Color
- Tan, yellow, or off-white
- 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: Tan, yellow, or off-white; Luster: Vitreous to dull; Crystal Structure: Hexagonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.6-2.7.
Formation & geological history
Formed from the metamorphism of quartz sandstone under high heat and pressure, causing sand grains to recrystallize and fuse together. Typically found in mountain belts (orogenic zones).
Uses & applications
Used in construction for road ballast, floor tiles, and countertop surfaces. Also used as decorative stone in landscaping and as a source of silica for glass manufacturing.
Geological facts
Quartzite is so durable that it often remains as caps on mountain peaks after softer surrounding rocks have eroded away. It is harder than steel and will easily scratch glass.
Field identification & locations
Identified in the field by its granular, sugary texture and extreme hardness. Commonly found in riverbeds as rounded cobbles like this specimen, smoothed by water transport.
More like this
