Quartzite

Hardness: 7 (Mohs scale), Color: Pinkish-red (due to iron oxides), Luster: Vitreous to dull, Crystal Structure: Granular/Crystalline, Texture: Non-foliated, sugary appearance.

Formed through the regional metamorphism of quartz-rich sandstone. High heat and pressure cause the quartz grains to recrystallize and fuse together, creating an extremely durable rock. The specimen shown appears to have surface algae or lichen growth.

Used in construction as crushed stone for road ballast, floor tiles, and decorative garden stone. Its hardness also makes it useful for industrial abrasives.

Quartzite is so strong that when it breaks, it fractures through the quartz grains rather than along the boundaries between them, unlike its parent sandstone. It is resistant to chemical weathering.

Identify by its extreme hardness (cannot be scratched by a steel nail) and grainy, sugary texture. Often found in mountainous regions or ancient shields like the Canadian Shield. The pink color specifically usually points to the presence of hematite.