ONYX, a variety of agate consisting of layers of variegated chalcedony, arranged in parallel bands. The colours of the successive strata vary in different stones, but in the typical onyx they are black and white. If one of the layers consists of the brown chalcedony known as “sard” or the red variety called “carnelian,” the resulting stone is termed a “sardonyx.” It was probably this kind of stone that originally suggested the name “onyx” (from owξ, a nail), since the contrast between its layers remotely resembles that between the flesh-coloured part of the finger-nail and the white lunula at its root. It was the practice of certain Greek writers to restrict the word owξ to the mineral in its natural condition, and to designate it, when worked into ornamental forms, by the diminutive ovvχu>v. When an onyx presents a thin layer of whitish chalcedony spread over a black ground, the upper stratum often exhibits a bluish tinge, and collectors at the present day term such a stone a nicolo, evidently a corruption of the Italian diminutive onicolo, or “little onyx.”...
India has for ages yielded the finest onyxes, and hence jewellers are in the habit of applying the expression “Oriental onyx” to any stone distinguished by beauty of natural colour and by regularity of its layers. The true Indian stones are found as pebbles, associated with moss-agate, jasper, and other silicious minerals in river-gravels, the materials of which have been derived originally from the agate-nodules of trap-rocks, such as those which occur on an enormous scale in the Deccan. As far back as the first century the author of the Periplus of the Red Sea mentions the onyx among the products of Plythanae, a locality which may probably be identified with Paithon on the Godavari, whence agates are obtained even at the present day. He further states that the onyxes were taken down to Barygaza, the modern Broach, where a great trade in agates is still carried on. It appears that the lapidaries of Broach and of Cambay are now supplied with raw stones chiefly from Ratanpur, in the territory of the rajah of Rajpipla, where the gravels are systematically worked for the sake of their agates, jasper, onyx, and other silicious stones. See Ball’s Economic Geology of India, 1881, p. 503.
The principal European locality for onyx is the neighbourhood of Oberstein on the Nahe, a river which flows into the Rhine at Bingen. Near Idar, about two miles from Oberstem, is a trap-hill called the Galgenberg, which for centuries was largely worked by means of tunnels driven into the hillside, in order to extract the nodules of agate which are embedded in the melaphyre forming the rock. When these nodules are broken open they occasionally yield a banded chalcedony which serves admirably for onyxes. The quarries have, however, been abandoned for many years in consequence of the discovery of larger and finer nodules in Uruguay, principally among the gravels of the Tarquarie and the Rio Pardo. These agates are still sent over in large quantities to Oberstein, where the cutting and polishing of such silicious stones form almost the sole industry of the locality. Coming from South America, they are commonly known in trade as “Brazilian agates”; and it is from these agates that most of our onyx is now obtained.
It is but rarely that the South-American agates present in their natural condition sufficient diversity of colour to constitute a good onyx, but for many years it has been the practice of the German agate-workers to colour these stones artificially. By this means an agate of dull colour may be rapidly converted into a deep-tinted onyx, the successive layers becoming sharply defined and vividly coloured during the process of staining. How this dyeing is effected has been described in the article Agate, vol. i. p. 277.
The onyx is largely employed for ring-stones, brooches, beads, and other ornamental objects; but its chief use is as a material for camei and intagli. By taking advantage of the different tints of the strata in this stone, a skilful artist is enabled to produce effects of a very pleasing character. Among the finest examples of ancient stone-engraving which have descended to us are certain vessels in onyx, elaborately ornamented with cameo-work, such as the Cup of the Ptolemies, the Farnese Tazza, and the Mantuan or Brunswick Vase.
According to the Authorized Version of the Old Testament, the onyx formed the eleventh stone in the breast-plate of the high priest; but it is more probable that this stone (DΠ⅛^) is the beryl, and that the onyx is □S∏', Exod. xxxix. 11 (E. V. diamond).
It is pointed out by the Rev. C. W. King that the earliest mention of the onyx as a precious stone is to be found in the inscriptions of the Parthenon, which date from the Peloponnesian War (431-404 b.c. ), where a large engraved onyx is mentioned as an offering. It is to be specially noted that ancient writers applied the term 6vυξ to two entirely different stones. While one of them was the true onyx of modern mineralogists, as described above, the other was merely a stalagmitic variety of carbonate of lime, a mineral much softer, less precious, and much more widely distributed than the chalcedonic onyx, yet resembling it in so far as it also presents a parallel-banded structure. This mineral is still known as “onyx-marble” (see Marble, vol. xv. p. 529).
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שהם, Gen. ii, 12; Exod. xxv, 7; xxviii, 9, 20; xxxv, 27; xxxix, 6; 1 Chron. xxix, 2; Job xxviii, 16; Ezekiel xxviii, 13. A precious stone, so called from the Greek ὅνυξ, _the nail_, to the colour of which it nearly approaches. It is first mentioned with the gold and bdellium of the river Pison in Eden; but the meaning of the Hebrew word is not easily determined. The Septuagint render it, in different places, the _sardius_, _beryl_, _sapphire_, _emerald_, &c. Such names are often ambiguous, even in Greek and Latin, and no wonder if they are more so in Hebrew. In Exodus xxviii, 9, 10, a direction is given that two onyx stones should be fastened on the ephod of the high priest, on which were to be graven the names of the children of Israel, like the engravings on a signet; six of the names on one stone, and six on the other. In 1 Chron. xxix, 2, onyx stones are among the things prepared by David for the temple. The author of Scripture Illustrated” observes, upon this passage, that “the word _onyx_ is equivocal; signifying, first, a precious stone or gem; and, secondly, a marble called in Greek _onychites_, which Pliny mentions as a stone of Caramania. Antiquity gave both these stones this name, because of their resemblance to the nail of the fingers. The onyx of the high priest’s pectoral was, no doubt, the gem onyx; the stone prepared by David was the marble onyx, or rather _onychus_; for one would hardly think that gems of any kind were used externally in such a building, but variegated marble may readily be admitted.”
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