Ceratonia siliqua harubh. "Ceratonia siliqua", the scientific name of the carob tree, derives from the Greek "kerátiοn" κεράτιον 'fruit of the carob (from "keras" κέρας 'horn'), and Latin "siliqua" 'pod, carob'. The unit "carat", used for weighing precious metal and stones, also comes from κεράτιον, as alluding to an ancient practice of weighing gold and gemstones against the seeds of the carob tree by people in the Middle East. The system was eventually standardized, and one carat was fixed at 0.2 grams. In late Roman times, the pure gold coin known as the "solidus" weighed 24 carat seeds (about 4.5 grams). As
Ceratonia siliqua a result, the carat also became a measure of purity for gold. Thus, 24-carat gold means 100% pure, 12-carat gold means the alloy contains 50% gold. The carob tree grows up to tall. The crown is broad and semispherical, supported by a thick trunk with rough brown bark and sturdy branches. Its leaves are long, alternate, pinnate, and may or may not have a terminal leaflet. It is frost-tolerant to roughly . Most carob trees are dioecious and some are hermaphroditic, so strictly male trees do not produce fruit. When the trees blossom in autumn, the flowers are small and