Actinolite occurs as coarse, brittle fibres with little tensile strength in altered diorite. The fibres occur in a series of north and west striking fractures for 61 metres along the bank of Wahleach Creek (Minister of Mines Annual Report 1960, page 133). Cairnes records the same occurrence but reports the hostrock as serpentinized peridotite (GSC Map 737A). Monger maps the locality as Proterozoic and Paleozoic Yellow Aster Complex (GSC Map 41-1989).