ONYX.
Onix, Onice, . . . Fn. Sang-i-Sulimani, . PERS. Sulimani pat'har, HIND. Oniks, . . . . Rus.
Onice, IT. Onique, Oniz, . . . Sr.
Pa'rmata unam, MALAY. Onix, Sw.
The onyx-stone is mentioned in Genesis ii. 12, but the term is said to have been applied also to the shell of a mollusc. This stone is a succes sion of plates of chalcedony. It is found in great abundance in the great greenstone tract of the Dekhan, and at Rajpipli in Gujerat, along with other chalcedonic and quartzose minerals. The silicious particles are arranged in alternating hori zontal layers of opaque, white, and translucent blue, grey, or brown, and because these have a resem blance to the marks on the human nail, the stone was called from the Greek word for nail, oyvZ. It was known to the ancients, and was employed by them, as it is now, for the manufacture of cameos, the figure being cut out of the opaque white, the dark part forming the ground, or the contrary. It is most valuable when the contrast of colours is strong, and when the layer is thick enough to give a high relief to the object to be engraved. In the royal library at Paris there is an antique cameo cut out of an onyx with four layers, representing the apotheosis of Augustus, eleven inches by nine, which is supposed to be the finest in existence. Agates with an onyx
structure are not uncommon, particularly among chalcedonies, but the finest are obtained in India. Cameos sold at Rome are made from a thick shell, having different-coloured layers. The onyx-stone is stained black by being boiled in honey, oil, or sugared water, and then in sulphuric acid. For red, protosulphate of iron is added ; and for blue, yellow prussiate of potash is added to the proto sulphate of iron. The onyx has a peculiar and almost superstitious value in the east, and is especially chosen for amulets. Chaplets of this stone are much esteemed. Colonel Tod had a vase, purchased in. Sindia's camp, evidently of Grecian workmanship ; and the numerous cameos of the onyx found in the Panjab, and other relics of Alexander's conquests, attest their abundance at times. In such numbers were these cameos found in 1803-4, when Lord Lake dictated peace to Holkar from the altars of Alexander, that the native artists of Muttra and Agra carried on a successful imitation of them for some time, which encouragement might have raised to celebrity. Eng. Cyc.; Emmanuel; Tod's Travels.