Quartzite Pebble

Hardness of 7 on the Mohs scale, colors vary from white and gray to pink or brown, vitreous to greasy luster, massive crystal structure with interlocking quartz grains, no true cleavage, specific gravity of approximately 2.65.

Formed from quartz-rich sandstone or chert that has been subjected to high heat and pressure, typically through tectonic compression in orogenic belts. Geological age can vary from Precambrian to Cenozoic.

Used in construction, railroad ballast, crushed stone for road surfaces, refractory bricks, and occasionally as decorative stone or in lapidary work.

Quartzite is extremely durable and resistant to chemical weathering, which is why quartz-rich rocks often survive as pebbles and boulders long after softer surrounding rocks have eroded away.

Found worldwide in mountainous regions and riverbeds where quartz-rich parent rocks have undergone metamorphism and subsequent water-wear. Identified by its extreme hardness, inability to be scratched by a steel knife, and interlocking crystalline texture visible under magnification.