The 15.99 carat Jubilee Ruby is the most costly colored gemstone ever sold at auction in the United States. It sold for $14.2 million, or $885,000 per carat, set in a spectacular gold and diamond setting by Verdura. The stone was offered by Sotheby's New York. Jubilee Ruby comes from Australia and is one of the largest gems found in that country. It weighs more than 14 pounds (6.5 kilograms) and measures 43 x 28 x 17 millimeters (1.7 x 11.0 x 0.7 inches). The rough gem quality of Jubilee Ruby makes it expensive to produce into a finished product. Colored stones are more valuable because they have better color and higher quality materials used in their production. For example, blue diamonds are rare and valuable because they are very hard to find and use in jewelry. The color comes from iron atoms inside the diamond reacting with organic molecules found in natural gas deposits beneath South Africa. Ruby is red carbon oxide (CO) mixed with black iron oxides (FeO). The word "ruby" comes from the Latin ruber, which means red. Rubies can be either natural or synthetic. Natural rubies are only available in small quantities and are extremely expensive. Synthetic rubies are much more common and affordable but they do not have the same quality as natural ones.