metamorphic
Red Quartzite (River Stone)
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Reddish-brown due to iron oxide impurities; Luster: Vitreous to waxy (when wet/polished); Crystal Structure: Non-foliated, granular; Specific Gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- Color
- Reddish-brown due to iron oxide impurities
- Luster
- Vitreous to waxy (when wet/polished)
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: Reddish-brown due to iron oxide impurities; Luster: Vitreous to waxy (when wet/polished); Crystal Structure: Non-foliated, granular; Specific Gravity: 2.6-2.7.
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone. Under intense heat and pressure, quartz grains recrystallize and fuse together. This specific specimen shows rounding from fluvial erosion (river action).
Uses & applications
Used as decorative landscaping stone, in construction as aggregate, for lapidary work/polishing, and historically as a tool stone due to its extreme hardness.
Geological facts
Quartzite is so tough that it often survives intense weathering that destroys surrounding rocks; it breaks across the quartz grains rather than around them, unlike its precursor sandstone.
Field identification & locations
Identify in the field by its hardness (will easily scratch glass) and granular texture that looks like sugar. Common in riverbeds and mountainous glacial tills.
More like this
