oil shale

oil shale

noun

Definition of OIL SHALE

: a rock (as shale) from which oil can be recovered by distillation

First Known Use of OIL SHALE

1873

oil shale

noun    (Concise Encyclopedia)

Any fine-grained sedimentary rock that contains solid organic matter (kerogen) and yields significant quantities of oil when heated. This shale oil is a potentially valuable fossil fuel, but the present methods of mining and refining it are expensive, damage the land, pollute the water, and produce carcinogenic wastes. Thus, oil shale will probably not be exploited on a wide scale until other petroleum resources have been nearly depleted. Estonia, China, and Brazil have facilities for producing relatively limited quantities, and the U.S. government operates an experimental plant in Colorado.