Tremolite

A very dark green (almost black) prism of tremolite. One end has a contact termination, the other has a nice termination which is hard to find.

The Miners Bay locality is within a dark gabbroic rock and did not appear to be the same cross-cutting structure that occurs in the standard vein-dyke of the Bancroft area. The exposure was approximately 5 to 6 meters long and 2 meters high in a road cut. The location has very well formed green amphiboles and less common tan coloured to slightly pink Microcline in a coarse-grained tan coloured calcite. The amphiboles from this area have been analyzed to be mostly Fe bearing tremolites, although some of them will be actinolite. There is no method of visually determining whether an amphibole from here is tremolite or actinolite.