The ruby is a gemstone known for its bright red color, although rubies can also vary in color from pink to dark red. The ruby is a very hard stone, second in hardness only to the diamond with a rating of 9 on the Moh's Hardness Scale. They are a popular stone used in jewelry, and a valued gem termed a "precious stone", one of a group of 4 stones (diamond, emerald, ruby and sapphire) that are considered precious. The Sanskrit word for ruby is "ratnaraj" or "king of precious stones". Many high quality rubies come from Myanmar, and rubies are also found in Africa, Asia, Australia, and Madagascar. The ruby is the birthstone for July. Interestingly, both ruby and sapphire are the same material, corundum, (an aluminum oxide, Al2O3).