Quartzite river stone

Hardness: 7 (Mohs scale), Color: Dull reddish-purple to brown, Luster: Dull/Waxy, Crystal Structure: Granular/Crystalline, Specific Gravity: 2.6-2.7. Smooth, rounded texture from water erosion.

Formed when quartz-rich sandstone is subjected to heat, pressure, and chemical activity of metamorphism. This specific specimen has been rounded into a 'river pebble' through mechanical weathering in a high-energy aquatic environment.

Used in construction as road ballast, gravel, or decorative landscaping stones. Highly durable for outdoor use.

Quartzite is so tough that it often outlasts the surrounding rocks during erosion, often forming the peaks of hills or mountains. It is harder than steel and cannot be scratched by a knife blade.

Identified in the field by its hardness (scratches glass), grainy texture that looks like sandpaper but feels smooth, and its lack of reaction to acid. Commonly found in riverbeds and glacial tills.