The Moore County meteorite in bulk composition resembles a Sudbury norite. The pyroxenes present were initially probably a single phase, pigeonite. This has undergone a complicated series of changes from which it is deduced that the temperature of the original environment was approximately 1135° C. and that the meteorite left this environment with catastrophic suddenness. Investigation of the fabric of the meteorite indicates a dimensional orientation of the plagioclase and pyroxene. The plagioclase b and c crystallographic axes and the pyroxene c axis tend to lie in one plane. The fabric is considered to represent primary layering developed by crystal accumulation on the floor of a magma chamber. Thus crystallization differentiation must have occurred in the original environment.