Steam has altered the surface rock into a gray clay and boiling mud. The Emerald Pool in the Southern Crater of Waimangu Valley. It is one of the craters produced by the 1886 eruption of Mt. Tarawera, which is no longer active. This is a cold water pool and colors vary with time. Warbrick Terrace named after a noted guide, is near Lake Rotomahana in Waimangu Valley.
Hot springs flow over terrances of white silica streaked by colors produced from minerals and algae.
Located in the Whakarewarewa Thermal Reserve, it is a favorite tourist attraction.