The Emerald , silica combined with alumina and glucine, scratches quartz with difficulty. Under this term are comprised the emerald properly so called and the aquamarine. When of a pure green hue, without any mixture of yellow or blue, it is the true emerald which comes from Peru, Egypt and Tyrol. So highly was it valued by the ancients that it was not allowed to be engraved, and it was preserved for its soothing effect upon the sight. Nero contemplated the combats of the arena through an emerald. The green sapphire, or oriental emerald, is much inferior in purity of tone to the emerald of Peru.

One of the largest known specimens surmounts the Pope's tiara.

The finest Aquamarines come from the Ural mountains, which also yield the finest Beryls. The latter are of a blue or greenish-blue tinge while the others are of a greenish-yellow or yellowish-green. In value both the aquamarine and the beryl are much inferior to the emerald, but when pure and of large size they still command a tolerably high price. One of the most remarkable aquamarines belongs to the Queen of England, while another equally famous is preserved in the Cabinet of Medals in the Paris National Library. It was engraved by the famous artist Evodus with a bust of Julia, daughter of Titus, and is no less than four inches high.

The GARNET, a combination of silica and alumina, scratches quartz, is usually of a red colour; refracts simply.

In the trade there are distinguished several varieties of the garnet: the pyrope of the lapidaries, an oriental garnet of a blood-red; the Syrian, a violet red; the Ceylon garnet, of a vinous red; the hyacinth, "la bella" of the Italians, ruddy brown; the deep-red hyacinth of the lapidaries, of a brownish orange. The dull colours of the garnet often render it necessary to hollow out its under side in order to give it greater lustre. Garnets have been found large enough to admit of being fashioned into little cups, and these always command a high price.