Quartzite is an unexfoliated metamorphic rock consisting primarily of quartz. It is usually a white rock, but occurs in other colors. It can occur in red, pink, yellow, blue, green and orange. The rock has a grainy surface with a sandpaper texture. When polished, it gains a glassy shine.
Rock forms when pure or nearly pure quartz sandstone undergoes heat and pressure. This is usually caused by tectonic compression. Sandstone sand grains fuse and recrystallize, cemented together by silica.
Sandstone quartzite is the intermediate stage between sandstone and quartzite. Sandstone is still considered a sedimentary rock, but it has an extremely high quartz content. However, it is difficult to identify the transition from sandstone to quartzite.
Some geologists use the term “quartzite” to refer to metamorphic rocks that consist almost exclusively of quartz. Other geologists simply identify “quartzite” as a firmly cemented rock found above or below a band of sedimentary quartz rock.
Composition
It consists almost entirely of silicon dioxide. Its purity is around 99%. Rock in this state is called orthquartzite. Quartzite usually contains iron oxide and may contain traces of the minerals rutile, zircon and magnetite. Quartzite may contain fossils.
properties
They have a hardness that is comparable to quartz and considerably harder than sandstone. Like glass and obsidian, it breaks with a conical fracture. Its coarse texture makes it difficult to sharpen a thin edge. Upon magnification, the interconnected crystal structure of quartzite becomes apparent.
Where to find
- Free Online Inclusive Education Course
- Free Online Toy Library and Learning Course
- Free Online Math Games Course in Early Childhood Education
- Free Online Pedagogical Cultural Workshops Course
Quartzite forms at the boundaries of the converging tectonic plates. Converging plates bury sandstone and exert compression. When the limit bends, mountains appear. Thus, quartzite is found in mountain ranges across the world.
While erosion drives away the softer rock, quartzite remains, forming peaks and cliffs. Rock also kills the sides of mountains like pebbles.
Uses
The strength and strength of quartzite lends itself to many uses. Crushed quartzite is used in road construction and railway ballast. It is used to make tiles, stairs and floors. When cut and polished, rock is very beautiful and durable.
It is used to make kitchen countertops and decorative walls. High purity quartzite is used to make silica sand, ferrosilicon, silicon carbide and silicon. Paleolithic humans sometimes made tools out of quartzite stone.
Quartzite vs. Quartz and Marble
Quartzite is a metamorphic rock, while quartz is an igneous rock. Sandstone under pressure becomes quartz sandstone and quartzite. However, quartzite does not become quartz. The construction industry further complicates the matter.
If you buy “quartz” for countertops, you are actually buying an engineered material made from crushed quartz, resin and pigments. It's not natural rock.
Another rock commonly confused with quartzite is marble. Both quartzite and marble tend to be light in color and not clad. Despite having a similar appearance, marble is a metamorphic rock made from recrystallized carbonate minerals and not silicates.
Marble is softer than quartzite. An excellent test to distinguish the two is to apply some vinegar or lemon juice to the rock. Quartzite is impermeable to acid attack, but marble bubbles and retains a mark.
The password has been sent to your email.
