Quartzite (Pebble)

Hardness: 7 (Mohs scale), Color: Grayish-white, Luster: Vitreous to dull, Crystal Structure: Hexagonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7

Formed through the metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize the quartz grains into a dense, interlocking matrix. This process can occur during mountain-building events (orogeny) over millions of years.

Commonly used as crushed stone in road construction, railway ballast, and as a decorative landscaping stone. In its high-purity form, it is used to produce silicon for glass and electronics.

Quartzite is so tough that it often survives intense weathering better than most other rocks, frequently capping hills and mountain ridges. It is harder than a steel knife and will easily scratch glass.

Identify by its extreme hardness and sugary, granular texture. Unlike limestone, it will not fizz in contact with acid. Commonly found in riverbeds, glacial deposits, and ancient mountain belts.