metamorphic
Quartzite pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: white to light gray with slight translucency; Luster: vitreous to waxy when wet; Structure: granular, non-foliated; Cleavage: poor/none (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- white to light gray with slight translucency
- Luster
- vitreous to waxy when wet
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 on Mohs scale; Color: white to light gray with slight translucency; Luster: vitreous to waxy when wet; Structure: granular, non-foliated; Cleavage: poor/none (conchoidal fracture).
Formation & geological history
Formed through the metamorphism of quartz sandstone under intense heat and pressure, typically in orogenic belts. These specific river-worn pebbles are likely from the Phanerozoic or Precambrian eras, redeposited in fluvial environments.
Uses & applications
Used as construction aggregate, railway ballast, and in the production of silica glass. Smooth river-worn specimens are popular for decorative landscaping and as 'worry stones'.
Geological facts
Quartzite is so tough that it often survives intense weathering that destroys other rocks, leading to its prevalence in riverbeds. It is often harder than the steel of a knife blade.
Field identification & locations
Identify in the field by its hardness (cannot be scratched by steel) and its granular, sugary appearance. It is commonly found in riverbeds, glacial tills, and mountainous regions like the Appalachians or Rockies.
More like this
