Nephrite jade is associated with an isoclinally folded dolomitic marble and calc-silicate rock horizon in the upper Gneiss Complex of the Cleve Metamorphics (Lower Proterozoic) near Cowell. Nephrite jade is known only within the nine square kilometres of the Cowell Nephrite Jade Province. Ninety-one separate nephrite jade lenses and pods ranging up to 65 metres long by 3 metres wide with average length to width ratio of 7.6:1, occur in surface outcrop. Colours of the nephrite jade are of green-yellow and green hue and vary from pale tones to black with increasing total iron content. Grain size ranges from fine to coarse grained and four distinct textures have been recognised. Fine grained black nephrite jade is the highest quality material and the most abundant in the province. Defects such as discolouration, present in surface material are unlikely to persist to depth. Rare inclusions of chrysotile, epidote, haematite, manganese dioxide, pyrite and tremolite have been recorded. Nephrite jade from Cowell is similar in chemical composition to jade from Alaska, Japan, Lower Silesia and New Zealand. The nephrite jade formed by metamorphism of impure dolomite to tremolitite with later tectonic recrystallisation of tremolite grains to fine grained, felted nephrite. This is in contrast to the association elsewhere in the world of nephrite jade with ultramafic rocks. Only four out of thirteen diamond drill holes intersected nephrite jade. An inferred 45,000 tonnes of raw nephrite jade are estimated to occur in the ground within the province. Assuming 10 per cent saleable material at $2 per pound, the potential value of the deposits before mining and processing is $20 million. Current world consumption of jade is approximately 700 tonnes per year. The jade is mined by opencast methods and trucked to Adelaide for slabbing and processing. Location: sections 111, 116, and 123, hundred of Minbrie, county of Jervois, and 22 kilometres north of Cowell. Minerals are reserved to the Crown.