Quartzite is a metamorphic rock having medium-grained texture. It is a derivative of sandstone. Read this CrystalBenefits article to know more about the facts, process of formation, characteristics, and applications of quartzite.
Most ancient statues recovered in Egypt are made out of carved quartzite. Some of them include the statue of Nakhthorheb kneeling in prayer, Ankhrekhu in a seated position, and the face of Senusret III.
The word quartzite is derived from a German word ‘quartzit’. It originates from its parent rock sandstone, which is known to be a sedimentary rock consisting a mixture of sand and quartz. This rock has a very low porosity, which implies that the grains in its structure are closely packed. They have a sugary texture. They are homogenous, strong, and offer strong resistance to rough weather conditions. Due to this property, sometimes it forms hilltops and ridges.
Quartzite is granoblastic and has a non-foliated grain structure with a glassy luster. The crystals in this rock have an interlinking pattern. These rocks break through the grains. They are also known to resemble marble.
Pictures of Colored Varieties of Quartzite
How is Quartzite Rock Formed?
Quartzite can be formed by two types of metamorphism processes: regional and contact.
These rocks are formed when some changes or processes take place on the earth. One of the processes includes the formation of mountains. In this case, rocks get compacted and crushed under high pressures. Due to this, a layered rock is formed which consists of minerals in varying proportions.
In places of high temperatures, rocks get heated up and melt. The reason for the high heat level can be some kind of igneous activity. The high-temperature melting of sandstone creates a granular structure in the resulting quartzite.
Some quartzite rocks are formed by a combination of both these processes. Consider the process of contact melting of a sandstone rock in a region of metamorphism.
Facts About Quartzite Metamorphic Rocks
▶ Quartzite can also be termed as metaquartzite.
▶ The metaquartzite rock is derived when the rock orthoquartzite undergoes the process of metamorphosis.
▶ The color of a pure quartzite rock is white. However, it exists in various others colors too, such as orange, brown, rose-pink, green, to name a few.
▶ Its composition depends on the composition of its parent rock. However, it is harder than sandstone.
▶ Since this rock contains quartz, most of its properties are similar to those of quartz.
▶ Its reddish or brownish shades are due to the content of iron oxide (Fe2O3) in it.
▶ Quartzite is found on the La Cloche mountains of Canada, Wasatch mountains of Utah, and Monte Binga mountain of Mozambique.
▶ In the United States, this rock is found in some parts of Texas, Dakota, Wisconsin, Arizona, and Minnesota. Besides this, other places where it is found are Austertena in Norway, Piedmont Region, Snive Quarry, Cuneo, Robilante regions of Italy, and Wasa Sten of Sweden.
Characteristics of Quartzite Rocks
▶ Density – Density is the mass per unit volume of a substance. The density of quartzite is 2.3 to 2.4 Kg/cm3.
▶ Loss on Ignition – A small quantity of quartzite is heated, thereby letting the volatile substances be released. Its loss on ignition percentage is less than 0.5%.
▶ Flexural Strength – It is the property of the rock which defines its ability to defy stress. Its value is 16-40 N/mm2.
▶ Water Absorption – The ability of the rock to soak water. The percentage of water absorption is as less as 1 – 1.2%.
▶ Hardness – Refers to the strength of the rock. The hardness of this rock is 7 units on Moh’s hardness scale.
▶ Compressive Strength – It is defined as the load that the rock can withstand without undergoing distortion. Its compressive strength is 90 to 140 N/mm2.
▶ Quartzite is highly resistant to alkalies and acids.
▶ Percentage composition: SiO2 – 93-94%, Alumina(Al2O3) – up to 1.5%, Iron(Fe2O3), Potash(KrO) and Soda(Na2O) – 1.1-1.2%, Lime(CaO) – 0.8-0.9%, Magnesia(MgO) – 0.2-0.25%
Uses of Quartzite Rocks
▶ In the pure form, quartzite can be used to make compounds of silica, such as silica, silicon carbide, etc.
▶ It is used to make beads and gems.
▶ It is used as a raw material in the ceramic and glass industries.
▶ It is used as an armor rock for making jetty/seawall structures.
▶ It is used as a decorative stone for construction purposes, and also in flooring, making roofing tiles, and staircases.
▶ It is used in making tabletops and counters in kitchens.
▶ It is also used in its crushed form for road construction, as well as making railway ballast.
Since ancient times, quartzite was known for its strength, and hence was widely used by the Stone Age man for the purpose of making tools. However, not only is it strong, but it also has a high resistance to extreme weather conditions, which makes it an apt raw material for many industries, including the construction industry.