Nephrite jade is associated with an isoclinatly folded dolomitic marble and calc-silicate rock horizon in the metasedimentary upper "Gneiss" Complex of the Cleve Metamorphics (Precambrian) near Cowell. Detailed geological, petrographic and chemical investigations of Cowell nephrite jade are described by Nichol (1974). The nephrite jade has 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 of nephrite jade elsewhere in the world with ultramafic igneous rocks, in particular, serpentine. Jade deposits in the Cowell area are a major resource as 45000 tonnes of raw jade are inferred in the ground within the province. On the basis of 10% of this being of market grade valued at $2 per pound, the potential total value before mining and processing is estimated at $20 million.