SHEBO Ozeo ; Sept. clxdrns ; Vulg. achates), a precious or rather ornamental stone, which was one of those in the pectoral of the high-priest (Exod. xxviii. 19 ; xxxix. 12). It seems not to have been questioned that some stone of the agate kind is intended. This stone is popularly known in this country under the name of Scotch pebble. Theophrastus describes the agate as ` an elegant stone, which took its name from the river Achates (now the Drillo in the Val di Noto) in Sicily, and was sold at a great price' (Kaltds Ka2 XiOor Kai 'Axdrns drb 'Axdrou 7rorai.toil rot', gy ELKAig Ka2 roAcirat Tii.tIOS, 58). This, no doubt, means that the stone was first found by the Greeks in the Achates. But it must have been known long before in the East ; and, in fact, there are few countries in which agates of some quality or other are not produced. The finest are those of India ; they are plentiful, and sometimes fine, in Italy, Spain, and Germany ; but those found in this country are seldom good.
We have no evidence that agates were found in Palestine. Those used in the desert were doubt less brought from Egypt. Pliny says that those found in the neighbourhood of Thebes were usually red, veined with white. Agate is one of the numer ous modifications of forrn under which silica pre sents itself, almost in a state of purity, forming 9S per cent of the entire mineral. The silicious par ticles are not so arranged as to produce the trans parency of rock crystal, but a semi-pellucid, some times almost opaque substance, with a resinous or waxy fracture ; and the various shades of colour arise from minute quantities of iron. The same
stone sornetimes contains parts of different degrees of translucency, and of various shades of colour ; and the endless combinations of these produce the beautiful and singular internal forms, from which, together with the high polish they are capable of receiving, agates acquire their value as precious stones._ Agates are usually found in detached rounded nodules in that variety of the trap rocks called amygdaloid or mandelstein, and occasion ally in other rocks. Some of the most marvellous specimens on record were probably merely fancied, and possibly some were the work of art, as it is known that agates may be artificially stained. Front Pliny we learn that in his time agates were less valued than they had been in more ancient times (Hist. Nat. xxxvii. to). The varieties of the agate are numerous, and are now, as in the time of Pliny, arranged according to the colour of their ground. The Scripture text shows the early use of this stone for engraving ; and several antique agates, engraved with exquisite beauty, are still preserved in the cabinets of the curious.—J. K.