The mineralogy and textures of specimens from a sulphide occurrence in a green schist at Waitahuna River are described, and their origin is discussed. The ore minerals are chalcopyrite, pyrite, marcasite, pyrrhotite, and minor sphalerite, and there is a small amount of supergene alteration. Marcasite, and the later of two main types of pyrite, are believed to have formed from pyrrhotite after the main stage of metamorphism, but are not supergene.