Rubies have been highly sought after for and used in jewelry for centuries. In Sanskrit ruby is called “ratnaraj” meaning king of precious stones. Historically, ruby has been highly sought after by royalty and the upper class. Ruby is a member of a species of stones known as corundum. Corundum is made up of two of the three most abundant elements in the earth’s crust: aluminum and oxygen. In order for corundum to form there needs to be an environment rich in aluminum and oxygen that is also has no silicon, the second most abundant element in the earth’s crust. Corundum comes in all colors, red corundum is commonly known as ruby where as blue corundum is sapphire. Rubies are rated as a 9 on the hardness scale. This means it is an excellent stone for use in ruby rings, ruby earrings, ruby pendants and any type of ruby jewelry. Ruby holds up to normal wear and tear better than emerald, amethyst, peridot and the vast majority of other precious stones with the exception of diamond.