Those born in April may rightfully boast that their stone, the diamond, is the most popular of all. Even in the days of Pliny, it was a prized possession: "The substance that possesses the greatest value, not only among the precious stones, but of all human possessions, is Adamas (diamond), a mineral which, for a long time, was known to kings only, and to very few of them." Not only because of its rarity and its hardness, but because it seems to gather unto itself the colors of all the other precious stones and to cast them forth in flashing, scintillating array it has long been ranked the king of jewels. Great was its power, in the minds of men. The Greeks and Romans firmly believed that the "elements", fire and water, had no effect upon it, and named it Adamas, meaning "subduing."

It was able to neutralize and overcome poisons, dispel deliriums and banish needless worry. It was a remedy for mania and it preserved virtue. Besides dissipating anger and strengthening love, it was an unfailing test for fidelity, because, it was said, a stone placed on the bosom of a sleeping loved one caused the heart to gush forth its most intimate secrets. The diamond was believed for centuries to be too hard to break. If placed on an anvil and struck with a hammer, it shattered both implements without harm to itself. The only method for conquering it was recited by Pliny in his Historia Naturalis: "This indomitable power, in fact, which sets at naught the two most violent agents in Nature, fire, namely, and iron, is made to yield before the blood of a he-goat. The blood, however, must be no other than fresh and warm; the stone, too, must be well steeped in it, and then subjected to repeated blows; and even then, it is apt to break both anvils and hammers of iron, if they are not of the finest temper."

This idea, like many others of the Romans, was dispelled by scientific investigation. Although the hardest known stone, much harder, in fact, than the hardest sapphire, and given a 10 on Mohs' scale, it breaks quite easily, for parallel to each of its eight faces are planes where the molecular cohesion is decidedly less than elsewhere, and the stone tends to split, or cleave, along these planes. This property is largely responsible for the reasonable prices of diamonds, as otherwise the cost of cutting them would be enormously increased. And he who would try the anvil experiment with his wife's solitaire had better prepare receptacles for the diamond dust! What is the diamond? Pure carbon. Carbon like that left on the bottom of saucepans, on the sides of lampchimneys, and in flues. Queer it is that this common substance, the Dr. Jekyll and Mr. Hyde of the mineral kingdom, appears so frequently as a messy nuisance, and so infrequently as a precious stone.