metamorphic
Quartzite
Quartzite (SiO2 silicon dioxide)
Hardness: 7 on Mohs scale; Color: typically white to gray, may have yellow or brown staining; Luster: vitreous to dull; Texture: granoblastic (interlocked grains); Cleavage: none.
- Hardness
- 7 on Mohs scale
- Color
- typically white to gray, may have yellow or brown staining
- Luster
- vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: typically white to gray, may have yellow or brown staining; Luster: vitreous to dull; Texture: granoblastic (interlocked grains); Cleavage: none.
Formation & geological history
Formed from the metamorphism of quartz sandstone under intense heat and pressure, typically during mountain-building events (orogeny).
Uses & applications
Used in construction for road ballast, floor tiles, and decorative stone; also used in glass making and chemical industries due to high silica content.
Geological facts
Quartzite is one of the hardest and most durable rocks. It is so tough that it often breaks through the quartz grains rather than along their boundaries.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by steel) and lack of reaction to acid. It is commonly found in ancient mountain belts and shield areas.
