Olivine facts for kids
Quick facts for kids Olivine |
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| General | |
| Category | Nesosilicate Olivine group Olivine series |
| Formula (repeating unit) |
(Mg, Fe)2SiO4 |
| Strunz classification | 9.AC.05 |
| Identification | |
| Color | Yellow to yellow-green |
| Crystal habit | Massive to granular |
| Crystal system | Orthorhombic |
| Cleavage | Poor |
| Fracture | Conchoidal – brittle |
| Mohs scale hardness | 6.5–7 |
| Luster | Vitreous |
| Streak | None |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 3.2–4.5 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.630–1.650 nβ = 1.650–1.670 nγ = 1.670–1.690 |
| Birefringence | δ = 0.040 |
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Olivine is a common mineral found all over the world. It is made of magnesium, iron, and silicate (silicon and oxygen). Its chemical formula is (Mg,Fe)2SiO4.
Olivine usually looks green. Its color can range from a bright chartreuse green to a lighter olive shade. When olivine is clear and beautiful enough to be used in jewelry, it is called peridot.
A rock called dunite is made of more than 90% olivine. Olivine is a very important mineral in the Earth's mantle. The mantle is the thick layer of rock beneath the Earth's crust. You usually don't find dunite on the surface, unless parts of the mantle have been pushed up by plate tectonics.
Olivine is not just found on Earth! Scientists have also found it in many places in space. It has been discovered on the Moon and in many meteorites (space rocks). It even exists in the dust clouds around young stars.
Contents
What Is Olivine Used For?
Olivine has several important uses in different industries. Its unique properties make it helpful for various tasks.
Olivine in Steel Production
Olivine is used in steel factories. It can replace another mineral called dolomite in some steel-making processes. Olivine is also used to plug the opening of blast furnaces in the steel industry. It acts like a stopper that is removed each time a batch of steel is made.
Olivine Sand for Casting Metals
The aluminum foundry industry uses olivine sand. Foundries are places where metal objects are made by pouring liquid metal into molds. Olivine sand is good for casting aluminum because it needs less water than other sands like silica sand. Less water means less steam is created when hot metal is poured, which helps the mold stay strong.
Olivine for Sauna Stoves
In Finland, olivine is a popular choice for sauna stoves. This is because it is very dense and can handle changes in temperature well. It resists breaking down even after being heated and cooled many times.
Images for kids
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Olivine seen under a microscope using special light.
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Crystals of olivine inside a slice of the Esquel meteorite.
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Figure 1: A close-up view of how atoms are arranged in olivine.
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Olivine that has changed into another mineral called iddingsite.
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Open-pit mining for olivine in Norway.
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Olivine grains from the green sand of Papakolea Beach in Hawaii.
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Light green olivine crystals found in basalt rock from Arizona.
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Bright green olivine from Pakistan.
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Olivine crystals found in lava from the Azores.
See also
In Spanish: Olivino para niños
