metamorphic
Quartzite Cobble with Iron Staining
Metamorphosed Quartz Sandstone (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs); Color: White to grey with yellow and rust-colored iron oxide staining; Luster: Vitreous to dull; Structure: Granoblastic, non-foliated; Cleavage: None
- Hardness
- 7 (Mohs)
- Luster
- Vitreous to dull
Identified More metamorphic →
Explore Quartzite Cobble with Iron Staining in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs); Color: White to grey with yellow and rust-colored iron oxide staining; Luster: Vitreous to dull; Structure: Granoblastic, non-foliated; Cleavage: None
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under heat and pressure. This specific specimen has been further smoothed via fluvial or glacial transport and weathered with iron-rich water.
Uses & applications
Primarily used in construction as railway ballast, crushed stone for road base, or as landscaping rock. Pure quartzite is used to produce glass and silica products.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks during erosion, often ending up as water-worn cobbles in riverbeds and glacial tills. It is one of the most durable rocks on Earth's surface.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by steel) and sandy, sugary texture on fresh breaks. It is ubiquitous in riverbeds, especially in areas with a history of glacial activity.
More like this
