Where is Quartzite found?
Metamorphic rock, primarily quartz (SiO2)
Got a photo? Identify rocks instantly with the Rockby app
Open the appQuartzite occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Quartzite
Appalachian Mountains, USA
Extensive quartzite formations, such as the Erwin Quartzite and Weverton Formation, are found throughout the Appalachian orogen, particularly in the Blue Ridge and Valley and Ridge provinces.
Baraboo Range, Wisconsin, USA
Famous for its Precambrian Baraboo Quartzite, known for its distinctive purple-red color and excellent preservation of sedimentary structures.
Scotland
The Cambrian-Ordovician Quartzite of the Northwest Highlands Geopark is a prominent geological feature.
Brazil
Significant deposits, particularly in Minas Gerais, known for high-quality quartzite used in construction and as a source of industrial silica.
India
Widespread occurrences in various mountain ranges and cratonic regions, used extensively as building material.
Collecting tips
- Look for Hardness. Quartzite is extremely hard (Mohs 7). It will scratch steel and cannot be scratched by a knife or common glass. This is a key differentiator from softer rocks.
- Examine Fracture. Observe the fracture pattern. Quartzite typically breaks across the original sand grains, creating a smooth, conchoidal, or subconchoidal fracture surface, often with a glassy luster. Sandstone, in contrast, tends to break around the grains, resulting in a more granular, friable surface.
- Check for Grain Interlocking. Under a hand lens, look for tightly intergrown, interlocking quartz grains. The original clastic texture of sandstone is largely obliterated in quartzite.
- Consider Geological Context. Quartzite is found in metamorphic terrains, often associated with other metamorphic rocks like schist, gneiss, and marble, or in areas that have undergone significant tectonic deformation.
- Acid Test (Caution). While not definitive for quartzite, a drop of dilute hydrochloric acid will not react with quartzite, distinguishing it from carbonate rocks like marble or dolostone which would effervesce.
Quick Check
- Color:
- White, gray, or various colors due to impurities
- Luster:
- Vitreous to greasy
- Streak:
- White
Explore Quartzite
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.