• A bull elk bugles in Yellowstone National Park

    Yellowstone

    National Park ID,MT,WY

There are park alerts in effect.
hide Alerts »
  • Craig Pass Closed for the Season

    The road linking West Thumb and Old Faithful is closed for the season—traffic should detour through West Thumb, Lake, and Canyon. More »

Emerald Spring

Bubbles rise to the surface, and steam from the surface, of this brighly green-colored hot spring pool.
 

A hot spring's color often indicates the presence of minerals. In a clear blue pool, the water is absorbing all colors of sunlight except one, blue, which is reflected back to our eyes. Here in Emerald Spring's pool, another factor joins with light refraction to give this spring its color. The 27-foot (8 meter) deep pool is lined with yellow sulfur deposits. The yellow color from the sulfur combines with the reflected blue light, making the hot spring appear a magnificent emerald green.

Hot spring water can dissolve and transport sulfur from underground. The mineral can deposit and crystallize at the earth's surface, sometimes in hot spring pools.


< Previous Stop | Next Stop >

Did You Know?

Upper Geyser Basin Hydrothermal Features on a Winter Day.

Yellowstone contains approximately one-half of the world’s hydrothermal features. There are over 10,000 hydrothermal features, including over 300 geysers, in the park.