Coorongite

Coorongite is a brown, viscous, hydrocarbon, somewhat similar in character to elaterite, of plant origin, found in Australia. It is not a mineral, but has its origin in the desiccated remains of the freshwater chlorophyte alga called Botryococcus braunii, and is combustible. Historical names for similar substances found in other parts of the world include balkashite, n'hangellite, and marahunite.

Initially it was thought to have been a source of oil for petroleum, and excited some interest in its potential for use as fuel, but interest waned as the facts became known. In recent years there has been some interest in its potential for use in the production of biofuel.