CAMÆA, in Natural History, a genus of the semipellucid gems, approaching to the onyx structure, being composed of zones, and formed on a crystalline basis: but having their zones very broad and thick, and laid alternately one on another, with no common matter between; usually less transparent, and more debased with earth, than the onyxes.

1. One species of the camæa is the dull-looking onyx, with broad, black, and white zones; and is the cameo of the moderns, and the Arabian onyx. This species is found in Egypt, Arabia, Persia, and the East Indies. 2. Another species of the cameo is the dull broad-zoned, green and white cameo, or the jasper cameo of the Italians: it is found in the East Indies, and in some parts of America. 3. The third is the hard cameo, with broad white and chestnut-coloured veins. 4. The hard cameo, with bluish, white, and flesh-coloured broad veins, being the sardonyx of Pliny's time, only brought from the East Indies.