Olivines from nearly 60 representative teschenite specimens from the Black Jack differentiated sill, near Gunnedah, northwest of Sydney, New South Wales, have been studied and data on their optical properties, derived compositions, zoning, and textural variation are presented. The composition range is Fa 21 - Fa 60 , crystals becoming increasingly fayalitic with progressive differentiation.

GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States