About the History and Uses of Onyx and Sardonyx

ONYX and sardonyx are varieties of agate with layers in even planes of uniform thickness, thus adapting them to the purposes of cameo engravers. The cameo has a base of one colour and the figure of another. The art of cameo engraving attained a point nearest perfection with the ancient Romans, evidence being supplied by the numerous relics, that are the admiration of modern artists. The word onyx means a finger-nail, and was suggested, it is supposed, by a fancied resemblance to the lustre and appearance of a finger-nail. Of course--if the Greek myth be true--this most beautiful instance of stratification in all mineral nature owes its origin to the freak of playful Cupid, and is the only visible and palpable evidence we have of the mundane visits of the Goddess of Beauty.

Sardonyx is a variety of onyx in which one layer has the brown colour of sard. Chalcedonyx and carnelionyx derive their names from the colours of the intervening layers. "Mexican onyx," it should be noted, is calcite, not quartz, and is very much softer than the real onyx. Mexican onyx has a similar banded structure to real onyx, and is well adapted to architectural or interior decoration, for which it is extensively used, but it is outside the realm of precious stones.

Because of their porous nature, varieties of agate can be easily artificially coloured, and this art has been developed to perfection in Germany, where some of the processes, as "trade secrets," are important phases of the general agate-preparing industry at Oberstein and Idar. The art of colouring agate, which naturally is mostly of a dingy grey colour, was derived from old Rome. Brazilian agate, the material extensively worked now in Germany, is softer than the German varieties that formerly constituted the principal supply, and is particularly susceptible to successful colouring by the scientific German processes.

The onyxes best suited for cameo engraving, besides onyx proper, are chalcedony-onyx, carnelian-onyx, and sardonyx. These are cut so as to display a white or light figure against a darker coloured background. Cameos are mostly engraved in Paris and Italy, but the plates of onyx used by these cameo engravers are prepared at Oberstein and Idar. The tool of the cameo engraver is known as a style.

Perhaps the most famous stone cameo in history was that sardonyx upon which Queen Elizabeth's portrait was cut, set in the famous ring which she gave the Earl of Essex as a pledge of her friendship. When sentenced to death, Essex sent this ring to his cousin, Lady Scroop, to deliver to Elizabeth. By mistake the messenger gave the ring to Lady Scroop's sister, Countess Nottingham, an enemy of the Earl; the vengeful Countess did not deliver the talismanic ring, and in consequence the fated Earl was executed. The Countess Nottingham confessed this act of vengeance to Elizabeth when the Countess was on her death-bed; which, according to the chroniclers of Elizabeth's life history, so infuriated the Queen that she shook the dying noblewoman, saying, "God may forgive you, but I cannot."