Elaterite
Elaterite, also known as aeonite, elasticite, elastic bitumen, or mineral caoutchouc, is a brown, often sticky, hydrocarbon. First discovered at Castleton, Derbyshire, in England, elaterite is not considered to be a mineral species. It has sometimes been confused with coorongite, found in Australia, but it has been determined that the origins of the two substances differ.