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Diamond, image, image, image, image, image, image, image, image, image,…
Diamond
Occurs in all shapes and sizes
Found in South Africa, Brazil, Namibia, Russia, Australia, USA, India
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India: Goleconda - Karnataka , Panna - Madhya Pradesh
Natural Diamonds
Natural Diamonds are formed by the action of high pressure and temperature on the carbon present in the earth at depths of 150 km. They are mostly brought to the surface by volcanic eruptions. Rocks that bear diamonds are called kimberlite rocks named after Kimberley Mines in South Africa
Artificial Diamonds
Artificial or Synthetic Diamonds are made from graphite. Graphite is introduced to a very high temperature (about 3000^C) and pressure in absence of air. The diamonds produced like this are comparatively smaller.
Value of Diamonds
The value of a diamond is based on:
Its weight (expressed in carat [1 carat = 0.2 g])
The impurities present in it
Note:
Colourless, transparent diamonds are the costliest because they have negligible impurity. The value of a diamond decreases with an increase in the impurities present in it.
Structure of a Diamond
A diamond is a giant molecule. The number of valence electrons in a carbon atom is 4.
Each carbon atom is linked with four neighbouring carbon atoms, forming a rigid tetrahedral structure. It is this strong bonding that makes diamond the makes diamond the hardest naturally occurring substance.
Since they have no free electrons, diamonds do not conduct electricity.
The basic tetrahedral unit of a diamond crystal is repeated infinitely forming a 3-dimensional molecule.
The shape of the crystal is octahedral.
Properties of diamond
Pure diamond is transparent and colourless. Impurities impact colours to diamonds.
It is the hardest naturally occurring substance. Black diamonds are the hardest of all.
It is of a brittle nature.
It has a refractive index of 2.5. Therefore, diamonds sparkle.
It has density of 3.5 g/cm3.
It is insoluble in any solvent.
It is a bad conductor of electricity.
Prolonged heating can change a diamond into graphite.
Uses of Diamonds
Pure diamond is used in jewellery as a gem dur to its brilliant shine.
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i. For cutting and drilling rocks, glass or other diamonds.
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