Ophitic lava outcropping along the southeast coast of King island, Tasmania, considered middle Cambrian in age, is composed of intergrowths of diopsidic augite and almost pure albite, partly altered to sericite. Some of the albite is considered to be primary, although the possibility exists that the intergrowth was originally between augite and a basic plagioclase with subsequent albitization. Hydrogrossular, in the same volcanic suite, occurs as pseudomorphs of olivine phenocrysts and also in veins and vesicles. It is hydrothermal. Chemical analyses are included.

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