Diamond is derived from the ancient Greek word adámas meaning “unbreakable”. It is an allotrope of carbon in which the carbon atoms are arranged in a structure called the diamond lattice.

Though graphite is more stable than diamond, the rate of conversion from diamond to graphite is negligible. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms.

Diamond has the highest hardness as 10 on Moh’s scale. This is used in the major industrial application of diamond in cutting and polishing tools.

Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated only by very few types of impurities. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds.

Small amount of boron makes the color of the diamond blue , nitrogen makes it yellow , defective lattice makes it brown, exposure to radiation makes it green, purple, pink, orange or red.

Diamond also has relatively high ability to disperse light of different colors. This is the cause of its characteristic luster. Diamond has been the most popular gemstone always.
Most natural diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers (87 to 120 mi) in the mantle of the Earth. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years or 1/4 to 3/4 the age of the earth.

Diamonds are brought close to the Earth′s surface through deep volcanic eruptions. Diamonds can also be produced synthetically in a process which simulates the conditions in the Earth mantle.

Diamond hardness depends on its purity, crystalline perfection and orientation. The hardness is higher for flawless, pure crystals. The hardest diamonds can be scratched only by other diamonds.

The hardness of diamond makes it the most suitable for daily wear. Because it can be scratched only by another diamond, it maintains its polish extremely well. Small wonder that engagement rings and wedding rings are made of diamonds.