Chemical analyses, cell parameters, and optical properties are presented for seven Scottish orthopyroxenes: four from Harris, two from Scourie, and one from Belhelvie, Aberdeenshire. The compositions range from En_83·6 to En_55·5. Six of the orthopyroxenes are from pyroxene granulites or related rocks and the other is from a plagioclase-hypersthene hornfels: the latter mineral is notable in having 7·21% Al₂O₃, causing a considerable contraction in the a and b cell parameters. The alumina content of orthopyroxenes is briefly discussed. Analyses are also given for olivine and diopsidic augite from a South Harris ultrabasic gneiss and for two enderbitic pyroxene gneisses from Scourie.