in places such as Crawford, Nebraska, for collectors to exchange rocks and socialize with other collectors. Often during erosion, agates were broken in half. These festivals and conventions give collectors a chance to find the missing half of an agate they found. The fairburn was designated as the state gemstone of South Dakota as of February 11, 1966, due to its prominence in the region and cultural impact with regard to collecting and decoration. References Agates Geology of South Dakota