Ironsand occurs extensively on the west coast of New Zealand's North Island. The sand makes up a large portion of the black-sand beaches on the North Island, as well as the surrounding sea floor. The magnetite in the sand contains fairly large quantities of titanium, and is sometimes referred to as titanomagnetite. It was produced from volcanic eruptions that occurred in the Pleistocene epoch, and is formed due to the oceanic erosion of the volcanic rock which is washed ashore by the waves to form the dunes of the black beaches. The magnetite is mixed with sand made from andesite and rhyolite. The sand mixture typically contains 5 to 40% magnetite.