oil shale - display specimen of oil shale from Parachute Canyon, Colorado
The oil shale of the Green River Formation underlies 1,500 square miles of the Piceance Creek Basin in northwestern Colorado. It contains a rubbery hydrocarbon called kerogen which becomes liquid when heated to 900˚F. In the 1970s, Occidental Petroleum planned to mine oil shale 1,500 feet underground, blast it to rubble in situ and siphon off the liquid hydrocarbon. Unocal planned to mine oil shale and retort it in a plant on the surface. Neither method ever became economical. There are huge reserves, with estimates in the early 1980s of 1.2 trillion barrels.
Kerogen has the same origin as petroleum and natural gas. The organic material in zooplankton rains to the sea floor in vast quantities. Buried by other sediments, it is then converted to kerogen by pressure and heating. Further heating produces petroleum, and even more heating natural gas. The oil shale in the Green River Formation originated as lake sediments deposited 50 million years ago.
Oil shale weathers to a whitish tan. Broken open, it is a dark brown, almost black These specimens are from the "mahogany layer," actually a kerogen-saturated marlstone, exposed in the walls of Parachute Canyon. It has a brittle fracture, almost conchoidal, unlike any other shale. Freshly broken specimens have the faint odor of kerogen, and yes, it does burn. Purchase a display or hand specimen, and if you want to experiment, we can include a small piece to use as a lab rat. Tap it with a hammer and sniff. Ignite it over a bunsen burner or with a propane cigarette lighter.
In 1882, pioneer Mike Callahan built a cabin with an oil shale fireplace. He ignored advice from local Utes, who said that the rock would burn. During the housewarming the shale of the fireplace ignited and the cabin burned to the ground.
Oil shale occurs worldwide, though in thinner deposits than in Colorado. It actually can be burned as a fuel in power plants. A plant near Narva, Estonia uses this fuel. Russia, Israel and Romania have used it in power plants, but have since converted to natural gas.
These specimens ship in a Regional Priority Mail box and can be combined in that box with other purchases.
Select a specimen: You can select a specimen by telling us what is in the photo with it, a blue or black and silver pen, a black mechanical pencil or one of those plus some number of coins, or you can let us make the selection. The specimen with a black pencil and coin has a weathered surface on the back.
Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. A link in that invoice will bring you back to checkout, no hassle.