Video - Gold mineralizationAt Fosterville the Gold occurs as both free gold and inclusions in sulphides (pyrite) and arsenides (arsenopyrite). Lots of sulphides and arsenides in the damage zone are good for gold values.
I will speculate that a sulphide-arsenide halo around the quartz veins is giving us the gold smoke. That will help target drilling as the drilling goes deeper.
Nice lookling rock!