What determines the weight
of precious gems?
By Chelsie Vandaveer
August 17, 2001
The carob (Ceratonia siliqua) [sair a toh' nee a sil' a qwa] is an evergreen tree native to the eastern Mediterranean. It produces a pod with bean-like seeds. The seeds are so much alike in size, weight, and density that they have been used since ancient times to weigh gold and precious stones. The Arabs called the seeds, qirat from which we derived the word, carat. The weight of the carob seed became the standard, 200 milligrams, handed down through the ages from Middle Eastern bazaars to New York diamond buyers.
Click here to view a photograph of carob seeds and pods. 
To view a photograph of the pods on the carob tree, click the link:
http://www.dipbot.unict.it/orto/0179-1.html
|
