Silica Rapids

Hiked in the Tongariro National Park along a creek and up through lava flows to what is called the Silica Rapids.  At first the rapids look like a yellow muddy creek, but the water is actually crystal clear.  When the stream emerges from lava cliffs at the head of the valley, the water is rich in aluminum and silicate minerals. As the stream gathers speed and the water is aerated, the aluminosilicates are deposited on the stream bed, which gives the streambed a mineral coating of yellow-white.

… and Mount Doom continues to lurk in the distance.