Emerald Pool is (pun intended) one of the jewels of Yellowstone National Park.
Located in Black Sand Basin, and sometimes called “Emerald Spring,” this feature has been delighting visitors to the Park for centuries and is rightly one of the Park’s most famous springs.
As to the name: According to Lee H. Whittlesey, writing in Yellowstone Place Names, Emerald was named by geologist (and Hayden survey member) Albert C. Peale in 1878, during the second of the Hayden surveys, who described it as having “beautiful emerald tint with yellow-green basin and ornamented edge.” Whittlesey also mentions a possible origin by way of a map produced by fellow Hayden surveyor Gustavus Bechler in 1872, which referenced a “Great Emerald Spring” in the basin. Per Whittlesey, under normal circumstances, Emerald Pool would actually be blue, but the presence of yellow bacteria tints it green.
As mentioned, Emerald Pool has been one of Yellowstone’s most popular springs, cropping up in travel literature and on postcards, such as the Haynes one above, produced around 1920.
To contextualize some of the historical mania for Emerald Pool, Whittlesey offers a passage from A Week in the Yellowstone by one J. Sanford Saltus, who waxes eloquently about the pool’s beauty:
Emerald Pool… is the most beautiful thing in the way of wonderland water I have ever seen, and I have seen many wonderful and beautiful lakes, lagoons, ponds, and pools in Europe, Asia, Africa, South America, Canada Mexico, the Mediterranean and West India Islands…Fill a thin goblet with Crème de Menthe, on the top drop a few “beads” of absinthe, and you will have a faint, only a faint idea of the glistening green glory of Emerald Pool, which can be compared to nothing unless one can imagine liquefied Chinese fire or the unknown, unnamable tones seen under the influence of an anesthetic or during delirium. Round the edge is a rim of sediment, exactly the color and apparent texture of rough-grained gold. Truly this is a jewel—an emerald set in gold! Were there nothing else to be seen in the Park, Emerald Pool would be worth the journey!
Today, visitors still marvel at Emerald Pool—the brooch of Black Sand Basin.