quartzite n : hard metamorphic rock consisting essentially of interlocking quartz crystals
- Finnish: kvartsiitti
Quartzite (from German Quarzit), not to be confused with the mineral quartz, is a hard, metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey. Quartzites often occur in various shades of pink and red due to varying amounts of iron oxide. Other colors are commonly due to impurities of minor amounts of other minerals.
In true metamorphic quartzite, also called meta-quartzite, the individual quartz grains have recrystallized along with the former cementing material to form an interlocking mosaic of quartz crystals. Minor amounts of former cementing materials, iron oxide, carbonate and clay, are often recrystallized and have migrated under the pressure to form streaks and lenses within the quartzite. Virtually all original textures and structure have usually been erased by the metamorphism.
Orthoquartzite is a very pure quartz sandstone composed of usually well rounded quartz grains cemented by silica. Orthoquartzite is often 99% SiO2 with only very minor amounts of iron oxide and trace resistant minerals such as zircon, rutile and magnetite. Although few fossils are normally present the original texture and sedimentary structures are preserved.
Quartzite is very resistant to chemical weathering and often forms ridges and resistant hilltops. The nearly pure silica content of the rock provides little to form soil from and therefore the quartzite ridges are often bare or covered only with a very thin soil and little vegetation.
UsesBecause of its hardness, about 7 on Mohs' scale of mineral hardness, crushed quartzite is often used as railway ballast. southwest Minnesota, Devil's Lake State Park in the Baraboo Hills in Wisconsin, the Wasatch Range in Utah, near Salt Lake City, Utah and as resistant ridges in the Appalachians and other mountain regions. Quartzite is also found in the Morenci Copper Mine in Arizona. The town of Quartzsite in western Arizona derives its name from the quartzites in the nearby mountains.
- R. V. Dietrich's GemRocks: Quartzite
- CSU Pomona Geology: Quartzite
- Cowen's "The First Geologists" (chapter on Stone Age/Homo habilis use of quartzite)
- Minnesota Department of Natural Resources : Natural History: Minnesota's geology
- Wisconsin's Baraboo Syncline (map and aerial photos of Baraboo quartzite quarries)
- South Dakota 2002 Mineral Summary: Production, Exploration and Environmental Issues (including 2002 quartzite production)
- Big Sioux River: History of Sioux Falls and Quartzite Photos
quartzite in Arabic: كوارتزيت
quartzite in Czech: Kvarcit
quartzite in German: Quarzit
quartzite in Estonian: Kvartsiit
quartzite in Spanish: Cuarcita
quartzite in Esperanto: Kvarcito
quartzite in Basque: Kuartzita
quartzite in French: Quartzite
quartzite in Icelandic: Kvarsít
quartzite in Italian: Quarzite
quartzite in Luxembourgish: Quarzit
quartzite in Lithuanian: Kvarcitas
quartzite in Dutch: Kwartsiet
quartzite in Japanese: 珪岩
quartzite in Polish: Kwarcyt
quartzite in Portuguese: Quartzito
quartzite in Russian: Кварцит
quartzite in Finnish: Kvartsiitti
quartzite in Swedish: Kvartsit
quartzite in Ukrainian: Кварцит