Preferential chemical etching of terrestrial And lunar olivines

A new chemical etching technique has been developed to study defect structures in terrestrial and lunar olivine crystals. Dislocations, low-angle dislocation boundaries, dislocation arrays and pile-ups have been observed on the (010, (100), and (001) faces of both polished and cleaved naturally deformed single crystal olivine, on various orientations of crystals in dunite, and in an experimentally deformed olivine crystal. Etching of Apollo 12 igneous rocks revealed dislocations and radiation damage tracks in lunar olivine. Dislocation etching of the (001) face of olivine is reported for the first time in this paper.