The twelve stones differed not only in color, but also in certain qualities peculiar to each, and both quality and color had especial reference to the tribe whose name it bore. Reuben's stone was the ruby, that has the property, when grated by a woman and tasted by her, of promoting pregnancy, for it was Reuben who found the mandrakes which induce pregnancy.
Simeon's stone was the smaragd, that has the property of breaking as soon as an unchaste woman looks at it, a fitting stone for the tribe whose sire, Simeon, was kindles to wrath by the unchaste action of Shechem. It was at the same time a warning to the tribe of Simeon, that committed whoredom at Shittim with the daughters of Moab, to be mindful of chastity, and like its stone, to suffer no prostitution.