metamorphic
Quartzite Pebble
Quartzite (primarily SiO2)
Hardness: 7 (Mohs scale); Color: Tan, orange-brown, or buff-colored due to iron oxide staining; Luster: Dull to waxy; Texture: Granular but smooth due to river tumbling; Cleavage: None (conchoidal fracture).
- Hardness
- 7 (Mohs scale)
- Luster
- Dull to waxy
Identified More metamorphic →
Explore Quartzite Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs scale); Color: Tan, orange-brown, or buff-colored due to iron oxide staining; Luster: Dull to waxy; Texture: Granular but smooth due to river tumbling; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone. High heat and pressure caused quartz grains to recrystallize and fuse. This specific specimen has been rounded and smoothed by water transport (alluvial processes).
Uses & applications
Commonly used in landscaping, as decorative gravel, or as a source for silica in construction. Smaller pebbles are often used in aquariums or as pathway stones.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks during weathering, often forming the high peaks of mountain ranges. It is harder than steel and can scratch glass easily.
Field identification & locations
Identify by its hardness (will scratch a stainless steel knife blade) and its granular, sugary appearance when broken. Very commonly found in riverbeds, glacial tills, and beaches worldwide.
