often confused by interpreters. Sard is carnelian, while sardonyx is a species of onyx. Sardonyx Sardonyx has a structure similar to onyx, but is usually composed of alternate layers of white chalcedony and carnelian, although carnelian may be associated with layers of white, brown, and black chalcedony. The ancients obtained onyx from Arabia, Egypt, and India. Topaz Topaz, Heb. ghtrh; Sept. topazion; Vulg. topazius, the second stone of the rational (Ex., xxviii, 17; xxxix, 19), representing Simeon; also the second stone in Ezech., xxviii, 13; the ninth foundation stone of the celestial Jerusalem (Apoc., xxi, 20) and also mentioned in Job, xxviii, 19. This topaz is generally believed to have been chrysolite rather than the more generally known topaz. Oriental topaz is composed of nearly pure alumina, silica, and fluoric acid; its shape is an orthorhombic prism with a cleavage transverse to its long axis. It is extremely hard and has a double refraction. When rubbed or heated it becomes highly electric. It varies in colour according to the country of origin. Australian topaz is green or yellow; the Tasmanian clear, bright, and transparent; the Saxon pale violet; the Bohemian sea-green and the Brazilian red, varying from a pale red to a deep carmine. The ancients very probably obtained it from the East. See also Priestly breastplate References Further reading Attribution The entry cites: ST. EPIPHANIUS, De duodecim qemmis in Patrologia Graeca, XLIII, 294-304; ST. ISIDORE, De lapidibus in Etymol., xvi, 6-15, in Patrologia Latina, LXXXII, 570-580; Charles William King, Antique Gems (2d ed., London, 1872); —, The Natural History of Gems or Decorative Stones (2d ed., London, 1870); BRAUN, Vestitus sacerdotum hebræorum (Leyden, 1680); BABELON in DAREMBERG AND SAGLIO, Dict. des antiquités grecques et romaines, s.v. Gemmæ; LESÉTRE in VIGOUROUX, Dict. de la Bible, s.v. Pierres précieuses; ROSENMÜLLER, Handbuch der biblischen Alterthumskunde (Leipzig); WINER in Biblisches Realwörterbuch (Leipzig, 1847), s.v. Edelstine. Biblical topics Gemstones in religion