in natural history, a common name for all precious stones; of which there are two classes, the pellucid and semi-pellucid.

The bodies composing the class of pellucid gems are bright, elegant, and beautiful fossils, naturally and essentially compound, ever found in small detached masses, extremely hard, pellucid, and of great lustre; composed of a very firm and pure matter, without any admixture of earthy substance, giving fire without steel, not fermenting with acid menstruums, and very difficultly calcinable in the fire.

The bodies composing the class of semi-pellucid gems are, stones naturally and essentially compound, not inflammable nor soluble in water, found in detached masses, and composed of crystalline matter, debased by earth: however, they are but slightly debased, and are of great beauty and brightness, of a moderate degree of transparency, and are usually found in small masses.