Diamond is an allotrope of carbon that is known for its hardness and dispersion of light which make it a valuable substance that is used as both an ornament and in industrial applications. Diamonds due to their hardness cannot be scratched by any other material making them suitable as abrasives. These minerals have been prized possessions more hundreds of years with their use in religious icons being documented up to 2,500 years ago. Their use in drilling bits and etching tools has also been seen in history.
Diamonds have increased in popularity mainly due to the increase in their supply as well as other factors such as improved cutting techniques and polishing. They are normally valued based on four criteria which are carat, clarity, cut and color.
They are normally cubic crystal systems that are made up of tetrahedrally bonded carbon atoms. This shape is the source of many properties of diamond, mainly its strength and hardness. It is the hardest known substance naturally occurring and this makes it useful in industry as well as in its suitability as a gemstone. A feature of diamond that is also evaluated is its toughness. This feature as opposed to hardness refers to its ability to resist breakage. Hardness only accounts for scratch resistance. Diamond has a fairly good level of toughness but this varies according to its geometry. They occur in a variety of translucent hues.
There have optical properties such as the ability to split white light into its component colors. The luster of a diamond the evaluation of how light interacts with the surface of a crystal, is brilliant and described as adamantine. Some diamond can show fluorescene. Blue diamonds are also good semi-conductors but most diamonds tend to be good electrical insulators. They are good conductors of heat even though they act as insultors mainly due to the strong covalent bonding in the crystals.