South Dakota’s State gemstone is the Fairburn Agate. Fairburn Agate is a semiprecious stone that was first discovered near Fairburn, South Dakota. Because of its coloration, it is sometimes referred to as Autumn Red.
Agate is a microcrystalline variety of quartz. Microcrystalline rocks are made up of many tiny crystals that can only be viewed with a microscope. Agate is yet another variety of Chalcedony.
Chalcedony is a catch all term that includes many well known varieties of cryptocrystalline quartz gemstones. They are found in all 50 States, in many colors and color combinations, and in sedimentary, igneous, and metamorphic rocks. Chalcedony includes carnelian, sard, plasma, prase, bloodstone, onyx, sardonyx, chrysoprase, thundereggs, agate, flint, chert, jasper, petrified wood, and petrified dinosaur bone just to name a few of the better known varieties. (Credit: U.S. Geological Survey)
Agate is known for the concentric patterns it creates and is frequently cut into slabs to show off it’s beauty.
Agate can be found all around the United States from Alaska to Wyoming. There are many types of Agate. Most are named based upon what they look like. For example, Crazy Lace Agate has varied lace like patterns and Moss Agate looks like the moss you might find growing on a tree or stone.