Rubies get their deep red color from chromium in the mineral corundum, which is also the hard foundation stone of sapphires. Rubies are rarer than sapphires, in part because sapphires encompass gemstones that range in color from blue to pink to orange. In contrast, rubies are always and only some variation of red, although jewelers have been known to market pink sapphires as rubies since rubies command a premium price. Although rubies are...Continue Reading