Terrain is rugged. The Island is made of granite, some of the oldest rock in New Zealand. A wide range of minerals are present, though not in commercial quantities. Tin was mined at Port Pegasus for a few years in the 1890's. There's black iron sand on some beaches, others are white with quartz or red with garnet.
Most beaches are gold, sparkling in the sun.
Paterson Inlet almost cuts the Island in half. This large expanse of water is popular for boat-trips and recreational fishing and diving. Climate is mild, and a trifle damp. No worry, without rain, there wouldn't be rain-forest. The eastern lowlands are forest, right to the water's edge.