Pink Quartzite

Hardness: 7 on Mohs scale; Color: Reddish-pink to purple; Luster: Vitreous to dull; Crystal Structure: Trigonal (granular); Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7

Formed through the metamorphism of quartz-rich sandstone under high heat and pressure, typically during mountain-building events (orogenesis). Often dates back hundreds of millions to over a billion years (Proterozoic to Paleozoic).

Used as decorative stone in architecture, railway ballast, road aggregate, and as a raw material for glass and ceramics. Also popular for lapidary work and garden landscaping due to its durability.

Quartzite is so hard and chemically resistant that it often forms the caprock or ridges of mountain ranges because it resists erosion better than the surrounding rock. The pink coloration is typically due to trace amounts of iron oxide (hematite).

Identify in the field by its extreme hardness (it will easily scratch glass and steel) and its crystalline, sugary appearance. Unlike sandstone, quartzite breaks through the sand grains rather than around them. Common in regions with ancient tectonic activity like the upper Midwest US or mountainous regions.