Reference to the illustrations will explain the following technical terms: _a_, the upper surface, is called the _table_; _b_, its sloping edge, the _beasil_; _c_, the girdle; _d_, the lower pointed portion, is called the _pavilion_, and the bottom plane, the _collet_. Of the thirty-two top facets only those are called _star-facets_ which touch the table; all the rest, as well as those below the girdle, are called _skill-facets_. The old "table diamonds," once so highly prized, may be described as having the table and collet greatly enlarged at the expense of the beasil and pavilion. The rose diamond is covered with equal facets, either twelve or twenty-four in number, the base of the stone being flat. This rule holds only for European roses; the Orientals covered their diamonds with irregular facets following exactly the shape of the stone, as with them the one object was to preserve the weight of the stone as far as possible. Chemically speaking, the diamond is almost pure carbon, and may be said to be first cousin to ordinary coal and half-brother to the smoke of an oil lamp. If the lordly gem should refuse to acknowledge such mean relations it can always be confronted with the "black diamond," which though an undoubted diamond, looks so very like a piece of coal that the kinship is evident. The present writer once saw a very costly _parure_ belonging to the Countess of Dudley, composed entirely of black diamonds set heavily in gold. Being a very little girl she considered it a great waste of the precious metal to employ it to set such ugly stones. She is of the same opinion still. In ancient times the diamond was credited with a vast number of occult virtues. Thus it was said by the Romans to baffle poison, keep off insanity and dispel vain fears. The Italians believed that it maintained love between man and wife, but we have already seen one notable instance in which it signally failed to render this useful service. One is at a loss to imagine how such a belief became common, seeing the number of diamonds which belonged to royal personages, and the state of affairs prevalent in their domestic life. In England, at the same period, diamonds were looked upon as deadly poisons. The murder of Sir Thomas Overbury in the Tower of London during the reign of James I. was said to have been attempted by means of these gems ground to powder. Overbury certainly died, and presumably by foul means, but modern science has acquitted diamonds of having any share in the crime.