Quartzite River Rock

Hardness: 7 (Mohs scale), Color: tan/off-white with sugary texture, Luster: vitreous to dull, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.6-2.7

Formed through the metamorphism of quartz sandstone under high heat and pressure, causing recrystallization of quartz grains. The rounded shape is the result of mechanical weathering and transport in a river or stream environment.

Used as decorative garden stone, in landscaping, as a construction aggregate, and occasionally as a source of high-purity silica for glassmaking.

Quartzite is so hard that it will scratch glass and even steel. Its interlocking crystalline structure makes it more durable than the sandstone it originated from.

Identify by its 'sugary' texture on the surface and high hardness (cannot be scratched by a knife). Commonly found in riverbeds, glacial deposits, and mountain outcrops where sandstone has undergone metamorphosis.