|Name origin||Philetus Norris, park superintendent (1877-82)|
|Location||Norris Geyser Basin, Yellowstone National Park, Park County, Wyoming|
|Elevation||8,448 feet (2,575 m) |
|Temperature||83.3 °C (181.9 °F) |
|Depth||27 feet (8.2 m)|
Originally named Emerald Geyser by Philetus Norris, park superintendent (1877–1882) because of its color, the name was later officially changed to Emerald Spring by the U.S. Geological Survey in 1930.
In 1892 Robert W. Wood, an American optical physicist, used the spring for a prank. He stealthy dissolved a pint of fluorescein in the pool to surprise several witnesses with unusually colorful water.
Emerald Spring is 27 feet (8.2 m) deep. The water temperature in the spring is around 83.3 °C (181.9 °F). The spring gets its name from the emerald green color of the water created by sunlight filtering through the water, giving the light a blue color, and reflecting off the yellow sulphur creating the green hue.
While Emerald Spring is a mostly calm pool, which usually only has a few bubbles rising to the surface, it does experience periods of turbidity and small 3-foot (1 m) high eruptions. In 1931, Emerald experienced a period of extremely vigorous activity with eruptions measuing 60 to 75 feet (18.2–22.9 m) in height.
- "Emerald Spring". Yellowstone Geothermal Features Database. Montana State University.
- "Emerald Spring". Geographic Names Information System. United States Geological Survey.
- Haines, Aubrey L. (1996). Yellowstone Place Names-Mirrors of History. Niwot, CO: University Press of Colorado. p. 148. ISBN 0-87081-383-8.
- Seabrook, W. (1941). "Alarms, excursions, and explosions at Johns Hopkins ending in early marriage and a job at the University of Chicago". Doctor Wood, Modern Wizard of the Laboratory. New York: Harcourt Brace.
- "Emerald Spring". Yellowstone Online Tours. National Park Service.
- "Emerald Spring". Geyser Observation and Study Association (GOSA).
- Ball, James W.; Nordstrom, D. Kirk; McCleskey, R. Blaine; Schoonen, Martin A. A.; Xu, Yong (2001). "Water-Chemistry and On-Site Sulfur-Speciation Data for Selected Springs in Yellowstone National Park, Wyoming,1996-1998" (PDF). U.S. Geological Survey. p. 26.