Olivine falls under the mafic and ultra mafic category of igneous rocks. It is light green to olive green in color with a molecular formula of (Mg,Fe)2SiO4 and therefore is a magnesium iron silicate. Olivine is a French word and is given due to its olive color. Apart from this it has many other names also like Chrysolite(in Greek), Evening emerald and Peridot. Peridot is also considered as august birthstone. Before coming to the earth surface they are in a molten form but once they come out they form crystalline structure.
Magnesium and iron ratio varies between the two end members of the series forsterite and fayalite. Forsterite(Fo) is a magnesium olivine and is known as magnesium silicate (Mg2SiO4) and fayalite (Fa) is an iron olivine and is known as iron silicate (Fe2SiO4). The purest form of olivine mineral is dunites and the peridotites hence these names frequently come under the uses of olivine. Olivine is not only found on the earth but it is also commonly found on the moon and other meteorites. Sometimes the content of olivine in a meteorite is about 50 percent.
Characteristic Properties of Olivine
To know about the characteristic properties of olivine just go through the table given below.
|Color||Yellowish green, olive green, dark green etc.|
|Transparency||Transparent to translucent|
|Crystal Habit||Massive to granular|
|Occurrence||Mafic and ultramafic igneous rocks and in some metamorphic rocks|
|Specific Gravity||4.3 for fayalite and 3.2 for forsterite|
|Index of Refraction||1.64 - 1.70 and has double refraction|
|Cleavage||Poor, imperfect but more distinct in fayalite|
Uses of Olivine
Olivine uses have proved it to be one of the most important minerals which is also found in abundance. Now you must be wondering what is olivine used for? There are many uses of olivine but the most important ones are as follows.
- Olivine is used as a slag conditioner and a refractory in the steel industry. In the refractory industry it can be useful as block olivine for furnace linings, ladle linings, patching compounds, crushed olivine mixed with a binder for refractory brick manufacture, etc.
- Olivine can be the most cost-effective raw material for the production of magnesium metal. This can be possible if the cost of silica produced be comparably similar to the cost of the fumes of silica. This can be done by dissolving olivine in a hydrochloride solution where silica is precipitated and the remaining solution is of magnesium chloride. This mixture can be easily separated and with the further processes magnesium metal can be obtained. Silica is also found in a 90% pure state. So we can consider it to be one of the economic uses of olivine.
- Researches are going on to make use of olivine to sequester CO2 and to a great extent scientists are even successful in doing so. We can say 1 liter of olivine can sequester approximately 1 liter of oil producing carbon-dioxide.
- Although people have become very practical and fast forward but still they believe in fortune and search for good luck. Yes this is the reason gemstones are so much in demand. Olivine mineral uses includes one such quality. People believe that olivine which is called peridot in the gem world, has some powers which can bring prosperity, health, peace, protection and love in their life. Peridot is considered as August birthstone and some even claim that it really works.
- Olivine is also used as an ornamental stone because of its beautiful olive green color. They are specially extracted for making jewelry. It has very beautiful glassy appearance which makes it more attractive and appealing.