Five members of the linnaeite series of sulphides linnaeite Co₃S₄, siegenite (Co, Ni)₃S₄, carrollite Co₂CuS₄, violarite Ni₂FeS₄, and polydymite Ni₃S₄ occur in nickel-sulphide-mineralized rocks in areas adjacent to the Kambalda and Scotia deposits of the Kalgoorlie district, Western Australia. Linnaeite, siegenite, carrollite, and polydymite occur in trace amounts as disseminated grains and veinlets. Violarite is also found as disseminations but its major occurrence is in the supergene enriched zones of the ore deposits. Aspects of their mineralogy, including mode of occurrence, general mineragraphy, reflectance at 546 nm, 589 nm and 644 nm, microhardness, and electron probe microanalyses are described.