A metallographic study of some hexahedrites

Abstract

Summary Large samples of the hexahedrites Scottsville, Indian Valley, Okano, Puripica, and Hex River Mountains from the British Museum Collection and a sample of Lombard have been prepared for metallographic examination and details of their structures have been mapped with the aid of a specially constructed X-Y plotting device that is geared to the stage of a metallurgical microscope. The following elements of structure have been studied and an attempt has been made to discuss the circumstances under which they were formed: clear etching and frosty etching kamacite, decorated Neumann lines, giant rhabdites, plate rhabdites, rhabdite clusters, microrhabdites, cohenite or decomposed cohenite, and troilite (which in some instances is recrystallized or remelted). In general the range of structural effects is similar to that previously reported for the Angra dos Reis hexahedrite (Min. Mag. 1971, 38, 94–101). The variations of structure are discussed in relation to nickel content and trace element chemistry of the meteorites.