The fountain towers in Iwama are located on the left bank of the Tedori river, close to the source of the Shin-Iwama Hot Springs.  Both have been designated Special Natural Monuments. The tower fountains are made of tufa, a kind of calcite rock that is from bodies of water with a high dissolved calcium content. Crystalline limestone melts from the heat of the hot spring water and this runs between rock cracks.  When the temperature rapidly cools, the runoff crystalizes and at Iwama, a beautiful tower of tufa is formed.  Geology and time come together to create this natural art.
  The tufa towers are either milk-white or orange in color.  The tops of these towers can shoot out jets of hot water that range from ten centimeter to three meters in height! The hot springs also sometimes produce a rainbow, at those times, the view of the fountains can be breathtaking. Tufa is present at some other hot springs as well, but this particular tower formation is quite rare.