X-ray diffractometry is a standard method for identifying and characterizing mineral phases in geological research. This proposal requests 50% of the cost of acquiring a modern x-ray diffractometer system to be installed in the Department of Geology of the University of Missouri in Columbia. The unit will replace a 25 year old instrument which is no longer functional for research purposes. Major current research projects in the department requiring x-ray diffractometry include the study of low-temperature chemical alterations altering the reservoir properties of Tertiary sandstone oil reservoir rocks, the effects of homoionic clay interactions on laboratory pyrolysis of kerogen (a petroleum precursor), and surface properties of mixed-layer illite-smectite clays from Gulf Coast sediments. Much of this research focuses on basic problems of the origin, migration and recovery of oil. In addition to its use by researchers in the Department of Geology, the diffractometer will be used by members of the Nuclear Research Center, Dalton Research Center, and the departments of physics, chemistry, and mechanical & aerospace engineering at Missouri. The university will contribute the remaining 50% of the cost of purchasing the equipment.