Onycha (, ), along with equal parts of stacte, galbanum, and frankincense, was one of the components of the consecrated Ketoret (incense) which appears in the Torah book of Exodus (Ex.30:34-36) and was used in the Jerusalem's Solomon's Temple. This formula was to be incorporated as an incense, and was not to be duplicated for non-sacred use. What the onycha of antiquity actually was cannot be determined with certainty. The original Hebrew word used for this component of the ketoret was שחלת, shecheleth, which means "to roar; as a lion (from his characteristic roar)" or “peeling off by concussion of sound." Shecheleth is related to the Syriac shehelta which is translated as “a tear, distillation, or exudation.” In Aramaic, the root SHCHL signifies “retrieve.” When the Torah was translated into Greek (the Septuagint version) the Greek word “onycha” ονυξ, which means "fingernail" or "claw," was substituted for shecheleth. Contenders for the identity of onycha Operculum Some writers believe that onycha was the fingernail-like operculum, or trap door, of certain sea snails, including Strombus lentiginosus, Murex anguliferus, Onyx marinus, and Unguis odoratus. It may be the operculum of a snail-like mollusk found in the Red Sea. This operculum is the trap door of a shell, called by the Latins Conchylium. These opercula may be of different sizes, but their overall shape is that of a claw, which is the origin of the name Unguis odoratus. The name Blatta Byzantina is occasioned by its having usually been imported from Constantinople, the ancient Byzantium. In antiquity the operculum was used as an ingredient in incense. The Baylonian Talmud recorded that onycha was rubbed with an alkali solution prepared from the bitter vetch to remove impurities, it was then soaked in the fermented berry juice of the Caper shrub, or a strong white wine, in order to enhance its fragrance. The operculum was also commonly used as an ingredient in many East Asian incense. Labdanum There is some doubt as to whether the onycha of the Old Testament was actually the operculum of a sea snail. H.J. Abrahams says, "The widely held mollusk hypothesis becomes quite perplexing if one considers that the mollusk was counted among the unclean animals in the Bible (Chapters Leviticus 11:9 and 12)." Sea creatures such as the mollusk were an “abomination” and even their carcasses were to be considered an “abomination” and anyone simply touching them became unclean. Rabbeinu