Colorado's Rocky Mountains aren't the only rocks the state is well known for. Diamonds and semiprecious gems can be found in nearly every part of the state. Experts and amateurs alike hunt for gemstones in the hills of Colorado and some of the largest diamonds in the world have been mined there. Colorado is also a rich source of many types of minerals and hosts many gold and coal mines.
The most valuable gemstone found in Colorado is the diamond and the most famous Colorado diamond is the enormous 45.5 carat Hope Diamond, now installed in the National Museum of Natural History. It was not originally mined in Colorado, but was purchased by Colorado's leading diamond miner, Thomas Walsh. However, the largest diamond mined in North America, which was 28.18 carats, was mined in Colorado. Kelsey Lake, Estes Park, Front Range, Cripple Creek and Green Mountain are some of the places in Colorado where diamonds are mined.
The state gemstone for Colorado is aquamarine, a crystal naturally occurring in a wide spectrum of shades of blue. Mines at Mount Antero and Mount White are some of the leading producers of aquamarine in the world.
Quartz is a crystal that is common not only in Colorado, but all over the world. Colorado is famous for the variety called smoky quartz, which is very dark and can grow to be several feet tall, though many other varieties of quartz also occur in the state. Quartz can be found in many colors ranging from white to purple to black.
Jasper is a stone that is frequently used in jewelry, sculptures and carvings. It can be found in Colorado in Park County and Mineral County in abundance. This stone occurs in reds, browns and yellows and, as it is easy to find, is a favorite for amateur rock collectors and polishers to gather, display and carve.
Agates are another gem found fairly commonly in the Colorado landscape, though there are numerous types of agate and some are rarer than others. New Raymer, Colo., boasts one of the rarest types of agate, the Fairburns agate, which is unusual because not only is it grown in a variety of colors, but it grows with many different colors blended in the same specimen. The Yampa River area in northwest Colorado also has proven to produce some Fairburns agates.