Rock Key Rock Identification Science Project Rock List Rock Key Shale Shale is a sedimentary rock formed from fine-grained sediments deposited in quiet, protected waters such as the deep ocean floor.
Shale is soft and porous.
Colours in shale result from the presence of minerals and organic substances. For example, black shale results from organic matter, red shale from ferric iron, and green shale from ferric iron. Shale is of considerable economic value. Oil is extracted from shale in the united states, Brazil, and south Africa. Petroleum from this source can not be refined by the same methods used to refine crude oil.