Amongst the many precious crystallised stones the diamond stands pre-eminent for beauty, brilliancy, and strength. It is the hardest stone known, hence the name of Adamas, meaning "the Indomitable," given it by its ancient discoverers, as with it every known substance can be cut, although it cannot be cut, nor be scratched by other stones; nor have acids nor solvents any effect upon it. It also resists the action of the file.

When found, the diamond is covered with a thick crust, so hard that there is no substance known that will remove it but that of itself, and it is only by grinding and polishing with diamond dust and minute diamonds that it is shaped and its wonderful brilliancy developed.

It was believed by the old writers to be the most powerful of all precious stones in its influence and effect upon humanity both spiritually and physically, and it is connected with marvellous records of adventure and enterprise, as well as representing Purity, Innocence, and protection from witchcraft and evil. To this day in India, amongst natives sufficiently wealthy, tiny diamonds are sprinkled from a white cloth over the heads of infants during the ceremony of naming the child, to keep it pure and virtuous.

The Romans also regarded the diamond with much reverence, fastening it upon the left arm so that the gem should touch the flesh, believing it powerful in making its wearer brave and daring, giving him the victory over his enemies; and when set in fine steel, was considered a charm against insanity.

It was thought by the old astrologers to be particularly powerful when worn by a subject born under a strong aspect of the planet Mars, bestowing fortitude, strength of mind, and constancy in wedded love; it repelled sorcery, poison, and nightmares, calmed anger, and strengthened friendship. It is often referred to as the Stone of Reconciliation; and was worn to promote love and harmony between man and wife.

Sir John Mandeville writes the following:

"A diamond should be worn on the left side of the body for it is of greater value there than on the right, for the strength of their growing is towards the North, that is, the left side of the world, and the left part of a man is when he turns his face to the East".

Another old writer says:

"He who carries a diamond on the left side shall be hardy and manly; it will guard him from accidents to the limbs; but nevertheless a good diamond will lose its power and virtue if worn by one who is incontinent, or drunken".

In the Middle Ages the diamond was thought to protect its wearer from the plague, and for this reason Queen Elizabeth was given a diamond to guard her against infection, which she is said to have worn in her bosom. It was a diamond worn in the girdle of Queen Donna Isabel II of Spain that saved her on the day when the murderous attempt was made upon her life. The point of the assassin's dagger struck the stone and glanced off, so the wound, which might otherwise have proved fatal, resulted in a flesh wound only. Napoleon, too, attached great value to the qualities of the diamond, and wore the famous Regent diamond in the hilt of his sword. The history of this remarkable stone is so curious that a brief account of its discovery and subsequent owners may be interesting. It was found at Parteal, south of Golconda, by a slave who concealed it by making a gash in the calf of his leg and hiding the stone in the folds of the bandage until he could escape to Madras. Deceived by the promises made to him by a sailor in whom he had confided, he consented, when a purchaser had been found for the stone, to share profits, but was thrown overboard by the seaman, who disposed of the diamond to a dealer named Jamchund for 1000, which he quickly spent, afterwards hanging himself.

The stone was next purchased by Thomas Pitt, grandfather to the Earl of Chatham, who purchased it after much bargaining for 20,400; but the jewel brought him no happiness. So fearful was he of losing it, it is said that he never slept twice at the same house whilst it was in his possession; also serious reflections were made on his character as to when and under what conditions he had obtained it. About the year 1717, having offered the gem to several sovereigns, the Regent of France was persuaded that his country should possess the most beautiful and perfect diamond known, so the purchase was effected for 135,000.

In its natural state it weighed 410 carats, but after its cutting, which took two years to complete, it was reduced to 137 carats, and was the size of a large plum, perfectly white, without spot or flaw, and of admirable water.

In the disorder attendant on the French Revolution the Regent diamond was stolen from the public treasury. Twelve years afterwards it was recovered, and subsequently was amongst the stones set in the Imperial diadem of France.

Another celebrated diamond is the Koh-i-Noor, or "Mountain of Light." Its history, according to Tavernier, the French traveller, can be traced back to half a century B.C. This stone is reported by Baber, the founder of the Mogul Empire, to have come into the treasury at Delhi from the conquest of Malwa in 1304, since when it has passed through the hands of many Indian rulers, who believed that the safety of their dynasty depended on the possession of this fateful jewel.

After many vicissitudes it came into the possession of Runjeet Singh King of Lahore, who wore it on his arm set between two smaller diamonds. So convinced was he of its mystical powers, that he bequeathed it to the Shrine of Juggernaut so that he might obtain benefits for his soul after death. His successors, however, would not allow the treasure to be disposed of in this manner, and it was subsequently presented to the late Queen Victoria by Lord Dalhousie on the annexation of the Punjaub, and was brought to London in 1850. The Brahmins believe that the Crimean War and Sepoy Mutiny, which occurred seven years afterwards, were due to its influence, and they say that misfortune will follow the possessor until it is restored to the line of Vikra-maditya ; but we are justified in the hope that as England is under the influence of the Zodiacal House of Aries, the house of the diamond, our Empire may still flourish and prosper.

Since the Koh-i-Noor came into our possession it has been recut, an operation which has decreased its size but greatly improved its brilliancy.

According to ancient lore, very large diamonds should never be worn as ornaments, as they bring disaster and anxiety; nor should they be used as sleeve-links or buttons or they will bring misfortune and sudden death. The losing of a diamond was considered (and still is), apart from its material value; an omen of mishaps. To be efficacious as a Talisman the diamond should be given freely, never sold, never lent, never coveted, and never taken by fraud or force. It is a curious fact that large diamonds have ever brought anxiety and often death to those who have taken them by violence and sold them; and the strange fatality which, for so many years, seems to have surrounded the famous Hope diamond is an example.