Black Opal Pool

The well-named Black Opal Pool is in Biscuit Basin near the Firehole River on the southwest side of Yellowstone National Park. The basin was named for the unusual biscuit-like formations that once formed the main feature of the basin but which were destroyed by the 1959 Hebgen Lake earthquake. The Firehole River is in the background of the photo and there is a fisherman in the river near the bend.