This invention relates to a super-active clay catalyst material prepared by a special method for treating clay materials, said catalyst for use in catalytic conversion of organic materials such as, for example, hydrocarbon compounds, heavy crude petroleum stock and kerogen. Said special method comprises contacting a clay material, existing in the raw state as found in nature or synthesized, with a solution containing cations selected from the group consisting of transition metal ions, aluminum ions, hydrogen ions, ions of metals from Group IIB of the Periodic Table of Elements and a combination thereof with each other, said clay material having been maintained at a temperature not exceeding about 100.degree. C. prior to and during the contacting with said solution, and thereafter heating said exchanged clay material to a temperature of at least about 50.degree. C. but not exceeding about 250.degree. C. in the presence of air and/or organic material which is to be catalytically converted. Further, this invention relates to in situ converting organic materials such as, for example, hydrocarbons, heavy crude petroleum stock and kerogen, by contact at low temperature, e.g. from about 50.degree. C. to about 250.degree. C., with said super-active clay material having been prepared in situ or transported thereto.