While lowland and alpine plants flourish elsewhere, the western Red Hills are home to Mount Aspiring's famous 'Mineral Belt'. The hills contain ultramafic/ultrabasic rocks, that are somewhat dark, and ferromagnesian minerals such as olivine. They hold silicates, metals and metal oxides but only little amounts of quartz. As a result, a low nutritious, partly toxic environment is generated - due to metals such as chromium and nickel.
The Red Hills soil also contain a high concentration of magnesium, a condition where plants hardly survive. Since this area lies upon several rare metallic elements such as tungsten, mining companies took notice and showed a particular interest in the Red Hill Range.