Quartzite is a metamorphic rock consisting mostly or completely of quartz1. In the vast bulk of cases, the is a metamorphosed sandstone.

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Pure quartzite is grayish absent with just one dominating mineral — quartz. Broad of sample 14 cm.

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The transition from sandstone come quartzite is gradational. There is tiny mineralogical change. Quartz, the key constituent of sandstone, is not transformed to other minerals if the sandstone is relatively pure, but it is recrystallized throughout the metamorphism. Original grainy look at of sandstone is lost to a change degree. Part quartzites space still similar to sandstones, only an ext strongly held together, while others are fully recrystallized so the all the attributes like fossils or original texture space obliterated and grain borders have disappeared. That is difficult to say wherein the boundary between these rocks exactly is. Absent sample that may be quartzite for one geologist can be strong cemented sandstone because that another.

Another common mineral in sandstone is stole oxide hematite. It gives reddish color to sandstones and it too is not altered during metamorphism. Many other minerals, however, can not pardon high temperature and pressure together well. Hence, impure sandstones may provide rise to quartzites the contain minerals favor mica, sillimanite, kyanite (metamorphosed clay minerals), pyroxenes and amphiboles favor diopside and also tremolite (metamorphosed dolomite add to silica native sandstone), and also even wollastonite (metamorphosed pure calcite cement with silica added) and many others. Quartz-rich muddy sediments normally metamorphose to schist due to the fact that there is too much aluminum-rich clay minerals. Quartzite commonly is the result of metamorphism if the resource material is relatively pure sandstone.

Quartzite is a typical metamorphic rock due to the fact that its protolith sandstone is very widespread. Quartzite outcrops can be discovered in plenty of mountain ranges all over the world. It generally is linked with existing or former mountain ranges since mountain-building is the process that is responsible because that the deep burial and also associated metamorphism that transforms sandstone come quartzite. Quartzite is a very hard rock. It tolerates weathering well because its main constituent quartz is really resistant come both physical and chemical disintegration. This properties make quartzite a useful building rock which is offered to develop walls, stair steps and floors. That is provided in road construction and as a railway ballast.

You might encounter terms like orthoquartzite and metaquartzite. The previous is actually a an extremely pure unmetamorphosed quartz-rich sandstone which is more commonly recognized as quartz arenite. Metaquartzite is more or less synonymous v quartzite. This terms room old-fashioned and little used nowadays2.

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Pure quartzite indigenous Telemark, Norway. Width of sample 9 cm.

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It is an extremely tough and also durable rock that consists of no pores and also unlike plenty of other metamorphic rocks that is not fissile or foliated. Width of sample 11 cm.
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Some relict bedding might be preserved. Width of sample 11 cm.
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Quartzite may resemble marble in ~ first. You may try to scrape the surface ar with a needle. If you deserve to do it, climate it is most likely marble. Another and also even far better test is to usage acid. Calcite, the key constituent of many marbles, reaction vigorously through dilute hydrochloric acid but there is no reaction v quartz. Broad of sample 13 cm.

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These contempt flattened clasts in conglomerate are made the quartzite. The rock created in the Ordovician and it was as soon as a riverbed. The outcrop is near Bergen in Norway.

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Feldspar-rich quartzitic absent – metamorphosed arkose. Aust-Agder, Norway. Broad of sample 19 cm.

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This dry cascading riverbed in Norway is written of quartzite.
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Red color is usually provided to the absent by steel oxide hematite. Width of sample 9 cm.
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It is a vein that quartz with pyrite cutting with quartzite. Broad of sample 11 cm.
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The sample native Finland is either strongly cemented sandstone or weakly metamorphosed quartzite. That is old (1.4 Ga) and also a component of crystalline basement. Hence, the is usually taken into consideration to it is in a metamorphic rock. Width of the sample 4 cm.
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This wall in western Ireland (Connemara) is constructed of regional quartzite blocks.
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Wall in Santorini, Greece. This material is local as well. Santorini is not completely volcanic island. The highest suggest of the island is a non-volcanic mountaintop of the Cyclades range.

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References

1. Barth, T. F. W. (2007). Quartzite. In: McGraw Hill Encyclopedia of scientific research & Technology

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, 10th Edition. McGraw-Hill. Volume 14. 722.2. Pettijohn, F. J., Potter, P. E. & Siever, R. (1973). Sand and also Sandstone
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. Springer.