DIAMOND IMAGE # 2: Carbon molecules shown in their crystalline arrangement in diamond. This image is 500 x 500 pixels; the original measures 4,096 x 4,096 pixels.
DIAMOND is the crystalline form (allotrope) of carbon. Each carbon atom is bonded to four others by covalent bonds. These strong and symmetrical bonds make diamond extremely hard. In this image, the carbon atoms are shown as black spheres at their covalent radii (i.e. just touching). Diamond is prized as a precious stone or gem and, because of its hardness, as an industrial material.
DIAMONDS AS JEWELLERY: Diamonds are highly prized as gemstones. Cut diamonds have been faceted to display their optical qualities to greatest effect.
INDUSTRIAL DIAMONDS are of lower quality than those used for gemstones in jewelry. The extreme hardness of diamond makes it an excellent abrasive and cutting material (e.g. in diamond tipped drills).