metamorphic

Quartzite

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale. Color: Highly variable, often white to pale gray, but can be pink, red, or purple due to impurities. Luster: Vitreous to waxy. Crystal structure: Massive. Cleavage: None. Specific gravity: 2.6-2.8

Hardness: 7 on Mohs scale
Luster: Vitreous to waxy

Identified September 1, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed by the metamorphism of pure quartz sandstone. Heat and pressure recrystallize the sand grains, interlocking them tightly. Common in many geological ages and environments, particularly areas of regional metamorphism.

Uses & applications

Used in construction, flooring, roofing, countertops, and as crushed stone for roads. Also popular among rockhounds and lapidary artists.

Geological facts

Quartzite is so tough that it breaks across the quartz grains rather than around them, unlike the sandstone it formed from. The red/orange coloring in this specimen is likely due to iron oxide impurities.

Field identification & locations

Identified by its granular, sugary texture, hardness (scratches glass), and lack of cleavage. Often found in mountainous regions or as river cobbles where it has survived transport due to its durability. A good stone for tumbling.