Hastings' Dictionary of the Bible (1898)
RU'BIES. There is much uncertainty concerning this translation. Some would render the word "red coral," and others "pearl" or "mother-of-pearl," both of which latter are often of a ruddy hue. The word occurs in Job 28:18; Prov 3:15; Jud 8:11; Prov 20:15; Prov 31:10; Lam 4:7, but seems never associated with the name of any precious stone. True rubies are of a red color. They are next to the diamond in hardness, beauty, and value, and once commanded even a higher price. See Stones, Precious.