Quartzite: Meaning (information, definition, explanation, facts)

Quartzite is a hard, metamorphic rock which was originally sandstone. Through heating and pressure inside the Earth, the sandstone quartz sand grains and quartz silica were fused into one.

Because of its hardness, crushed quartzite is often used as railway ballast. In the United States, formations of quartzite can be found in eastern South Dakota and southwest Minnesota.