the sides with clean-cut faces. The space group of murdochite has been confirmed to be Fm3m. Murdochite can be cubic, with a point group of 4/m 3 2/m, or octahedral and cubo-octahedral whose point group is 2 mm. Murdochite can occur in the forms (100) and (111) with crystal twinning being very common. The calculated density of murdochite was determined to be 6.1 g/cm3 and have a measured density of 6.47 g/cm3. Geologic occurrence Naturally occurring murdochite, (x ≤ 0.5), was discovered in Mammoth Mine, Arizona. The mine, about 46 miles northeast of Tucson, contains deposits of molybdenum, lead, gold, zinc, vanadium, sphalerite, and galena. In this mine, murdochite was found embedded in plates of wulfenite as well as on the surface of crystals of fluorite. Other crystals found in Mammoth Mine include hemimorphite, willemite, and quartz. Larger masses of murdochite have also been found at the T. Kguni Mine in Anarak, Iran. Here murdochite was found in conjunction with khuniite (iranite), chrominium (phoenicochroite), plumangite and an unknown mineral with the formula Pb9O16. All these minerals are lead oxide minerals, meaning that murdochite can be found in oxidized Pb-Cu deposits. More recently, small murdochite crystals were found encrusting aurichalcite crystals in the Granite Gap Mines in New Mexico. Origin of the name The mineral murdochite is named after Joseph Murdoch, who was once a professor of geology at the University of California, Los Angeles and a past president of the Mineralogical Society of America. Professor Murdoch was born February 19, 1890, and died December 31, 1973, at 83 years of age. Murdoch obtained a baccalaureate degree, an M.S. and a Ph.D. in geologic science by 1915 from Harvard University and would first be involved in a non-geological business career before joining the faculty at the department of geology at the University of California, Los Angeles in 1928. It was here that Murdoch returned to work in the geologic field that would lead to the publishing of numerous papers which would include 23 publications ranging from the years 1913–1968, along with ten published abstracts and many book reviews. See also List of minerals List of minerals named after people References Oxide minerals Copper(II) minerals Lead minerals Cubic minerals Minerals in space group 225