Abstract
Unit-cell parameters for synthetic members of the diopside-hedenbergite series have been determined by least-squares refinement for 26 samples consisting of 11 compositions. Within the experimental error, the cell volume and cell edges a and b appear to change linearly over the entire compositional interval, although /3 does not. The c dimension is not sensitive to the Mg/Fe ratio. No significant difference was observed for samples synthesized on different oxygen buffers.
Four reflections were used to test the validity of a spacing curve for estimating the compositon of clinopyroxenes from calc-silicate skarns. Eight samples from Willsboro, New York indicate that the composition of clinopyroxenes coexisting with vvol lastonite and garnet can be estimated to within ± 5 mole percent if elements other than Ca, Fe, Mg, Si, and 0 are known to be present in only very low concentrations.
