metamorphic
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Hardness: 7 on Mohs scale; Color: typically white, gray, or yellow with iron staining; Luster: vitreous to waxy; Texture: granular or sugary; Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- typically white, gray, or yellow with iron staining
- Luster
- vitreous to waxy
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Physical properties
Hardness: 7 on Mohs scale; Color: typically white, gray, or yellow with iron staining; Luster: vitreous to waxy; Texture: granular or sugary; 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 specimen shows signs of fluvial erosion (river weathering).
Uses & applications
Used in construction as crushed stone, for road ballast, as a source for silica in glassmaking, and frequently as decorative landscaping stone.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rock in mountain ranges, forming ridges. It is one of the most durable and weather-resistant rocks on the Earth's surface.
Field identification & locations
Identify in the field by its hardness (will scratch glass easily) and its tendency to break across quartz grains rather than around them. Found globally in ancient mountain belts.
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