In April 1988, this geyser blasted through the boardwalk (which was rerouted)
and has cinnamon-red deposits flanked by black obsidian sand.
The constant eruption is about a foot high.
Black Sand Basin is named for the black obsidian sand around the thermal features.
Obsidian is formed when lava cools too quickly for mineral crystals to form;
it’s a natural form of glass.
Yellowstone National Park