As long as about three thousand years ago, the man bent down to pick up a glistening pebble and by some chance found it to be different from other stones. From that time, diamonds began to acquire magical powers and to be regarded with awe, worship and avarice. More recently it has become an object of extreme scientific curiosity. The man began to collect diamonds, treasure them, build legends around them, trade-in them, use them as tools, treat them as gems, raise loans with them, fight over them, and eventually give them as symbols of love and trust. His early instinct to treat diamond as unique was true because today probably more effort goes into discovering the nature of diamond than into research on any other material.
The desire for diamond because of its beauty as a gem, apart from its scientific and industrial uses, has not dimmed over the years but has become much more widespread. A century ago, the possession of a diamond was the prerogative of the rich alone. Since the discovery of huge deposits in Africa, and more recently diamond pipes in Russia, intensive mining and marketing of diamonds has brought them within reach of large sections of the populations of industrial countries, both as gems and as parts of working tools. Diamond is the hardest substance man has ever discovered and the purest that occurs in Nature. Although very highly prized as a gem, however, it is composed of one of the commonest substances on earth, ordinary carbon. Carbon is found in all living things, plants as well as animals, and in many rocks. Diamond can be broken with the blow of a hammer, yet will penetrate steel by pressure. It is extremely durable, being able to withstand attack by the strongest acids and alkalis, yet is an unstable form of carbon and will burn or oxidize on the surface if dropped in a fire for a short time. It has a very high melting point and will cut steel for long periods at near red heat. Yet heated to bright red it will catch fire and convert to carbon dioxide gas. 
Origin of the Name
Adamas and adamant were words implying extreme hardness, derived from the Greek adamao meaning 'I tame' or 'I subdue'. They were used in classical times to describe sapphire (corundum), which was sometimes confused with diamond. In the Bible, God tells the prophet Ezekiel 'As an adamant harder than flint have I made thy forehead.' Adimantum, a common Greek variation of adamant, is probably the root word of the old French diamant and the English dyamaund and adamaund, used at the beginning of the fifteenth century, as well as the poetic dimaund. The modern spelling originated in the mid-sixteenth century.
For many centuries, adamant referred to lodestone as well as hard materials such as diamond and corundum, owing to confusion with the Latin word adamare, 'to attract'. William Shakespeare used it in this sense at the beginning of the sixteenth century in Troilus and Cressida with the words, 'as a turtle to her mate./'As iron to adamant', but about sixty years later, John Milton was employing it in its original sense in Paradise Lost: 'Three folds were brass,/ Three iron, three of adamantine rock 'Adamantine, as used today, refers to the quality of impenetrable hardness, as in the adamantine lustre of a diamond's polished surface.
The Hardness of Diamond
The Roman philosopher, Pliny the Elder, wrote: "These stones are tested upon the anvil, and will resist the blow to such an extent as to make the iron rebound and the very anvil split asunder.' The belief persisted for centuries. In the year 1476, Swiss mercenaries found diamonds belonging to Charles the Bold, Duke of Burgundy, after the battle of Morat, and struck them with hammers and hatchets to discover whether they were genuine, with the result that they powdered. Many fine diamond crystals were broken in the same belief by miners of the Indian mines from the fifteenth century to those of the early diamond diggings of South Africa in the last quarter of the nineteenth. It was said by Jean Baptiste Tavernier (1605-89) who was a French jeweller and one of the first "globe-trotters', after he visited the Indian mines in the seventeenth century, that some merchants knew the true facts. They persuaded miners that stones they found were not diamond by breaking them with a hammer, then picked up the pieces after the disappointed miners had left.
Diamond cut Diamond
The truth is that, because diamond is the hardest known substance, it has relative brittleness. The two properties are different. Other materials are also brittle because they are hard, such as sewing needles and metal files. The eminent scientist Sir William Crookes used to demonstrate the hardness of diamond by placing a crystal between the jaws of a vice and tightening the vice. Diamond cannot be deformed plastically by normal forces, so the crystal penetrated the hardened steel jaws and did not break - an experiment that had been previously reported by Ibn Mansur in the thirteenth century. One aspect of the hardness of diamond is, then, its extreme resistance to being deformed. Another is that it cannot be scratched except by other diamonds. But it resists scratching by another diamond in some directions more than in others. A diamond used in one of the harder directions will therefore cut another diamond in one of the 'softer' directions. That, and how to find the hard and 'soft' directions, was a secret kept for centuries by diamond cutters and engravers. King Charles I of England was aware of the fact that powered diamond could be used to abrade a diamond (in a 'soft' direction). The night before his execution, in 1649, he wrote: a With my own power my majesty they wound In the King's name the King's himself uncrowned So doth the dust destroy the diamond.'
Diamonds in Social History
The wearing of jewellery is as ancient a custom as any on record and appeared in early societies to be of primary importance after the seeking of food and shelter. It has been conjectured that the wearing of pretty stones was originally motivated by a desire to remember the spring with its promise of food and warmth, and later became the personal adornment or the symbol of rank or wealth that it is today. Large diamonds were badges of rank worn by rulers and also convenient portable wealth in the early days of India. Most of the historical diamonds that still exist are Indian, and all have had eventful and sometimes bloody histories. Tavernier brought a number of them to Europe. The Koh-i-Nûr, or Mountain of Light, has the longest history of all famous diamonds as it was known to be in the possession of the Rajahs of Malwa as long ago as 1304 and was facetted no later than 1530. It is believed to have been set by the Mogul emperors in the famous Peacock Throne as one of the peacock's eyes. The other eye was the Akbar Shah diamond. The Persian Shah took the diamond when he invaded India and later it came into the hands of the 'Lion of the Punjab' who accepted it in return for military help that he never gave. Eventually, it was taken by the East India Company against losses and presented to Queen Victoria.
The 410 carat Regent Diamond played a part in the French Revolution. It was one of the last big diamonds to be found in India, in 1701. It came to England and was named 'the Pitt, and the major part after recutting was resold to the Regent of France when it acquired its current name. Later Marie Antoinette wore it and on 17th September 1792, it was among the French Crown jewels that were stolen during the early stages of the French Revolution. Most of the treasures were quickly recovered but the Regent diamond did not come to light until fifteen months later when it was found in a hole in a beam of a Paris garret. During the Directoire period, the Regent and other diamonds were pawned to a Berlin banker for 4,000,000 francs to keep fourteen French armies in the field. It was redeemed and then used as a guarantee for a loan from a Dutchman. After it was again recovered, Napoleon Bonaparte had it set in the hilt of a sword he carried when being proclaimed Emperor of France.
