Diamond is made of carbon, and is the hardest natural mineral. The name comes from the Greek "adamans", which means "invincible". While of course they are used for jewelry, their hardness makes them particularly useful in industry and manufacturing for cutting and grinding. They have been in use for jewelry since the 4th Century BC.
Throughout much of history, diamonds have been considered the King of Gems. In the Eastern world, diamonds were thought to have the power to bring good fortune, and to attract the power of planetary influences so strongly as to render the wearer invincible. Medieval Italians called it the stone of reconciliation because it was thought to bring peace between husband and wife, which began the tradition of incorporating diamonds into wedding or engagement rings. Later, the Baron d'Orchamps said that if diamonds were worn on the left hand, they warded off evil; thus beginning the tradition of wearing a diamond on the left ring finger.
In religious use, it has been a symbol of authority and was an intermediary between the human and divine worlds. In ancient Israel, the diamond was reputed to show the guilt or innocence of an accused person - if the person was guilty, the diamond would grow dull; if the person was innocent, it would shine out with its glory increased tenfold. The diamond symbolized innocence, justice, faith, strength, and the impassivity of faith.
Pliny the Elder said that diamond had the ability to protect its wearer, to make him courageous and daring - and, if worn on the left side, to give him victory over his enemies in court or in war, if his cause is just. During the Middle Ages, a diamond was thought to be an antidote for all poisons when worn in a ring; however, if ingested it was thought to be the most deadly of all poisons.
An old superstition has it that a diamond loses its power if acquired by purchase, as the spirit of the stone may be offended by being bought or sold. However if the stone is freely given, or is given as a token of love or friendship, the spirit is willing to transfer its benign powers to the new owner.
Diamond is a powerful love stone. It bonds relationships and enhances love, increases harmony and engenders trust between two partners. As a symbol of love and fidelity, diamonds have been given in engagement and wedding rings since the 15th Century, although the huge popularity of diamonds as the most popular stone for engagement rings was created by DeBeers in the early- to mid- 20th Century.
Diamond is particularly associated with the Crown chakra. It is the traditional birthstone for April, and is linked to the astrological signs Aries, Cancer, Leo and Taurus; it is also the official anniversary stone for the tenth and sixtieth year anniversaries.