Opal Pool

Opal Pool in Yellowstone National Park is one of the park’s most delicate and visually stunning hot springs, located in the Midway Geyser Basin — the same geothermal area that houses the world-famous Grand Prismatic Spring and Turquoise Pool. Although smaller and quieter compared to its neighboring features, Opal Pool holds a charm that fascinates visitors with its enchanting colors, peaceful surface, and occasional geyser-like activity. This thermal feature perfectly captures Yellowstone’s mystical geothermal beauty, offering an intimate experience away from the more crowded viewpoints.

Note: Opal Pool (Midway Geyser Basin) and Black Opal Pool (Black Sand Basin, near Old Faithful) are not the same, though their names sound very similar and they both belong to Yellowstone’s geothermal family.

 

Opal Pool

Quick Reference: Opal Pool

Category	Details
Name	Opal Pool
Type	Hot Spring (occasionally acts like a geyser)
Location	Midway Geyser Basin, Yellowstone National Park, Wyoming
Nearby Landmarks	Grand Prismatic Spring, Turquoise Pool, Excelsior Geyser Crater
Temperature Range	Approximately 160–190°F (71–88°C)
Color	Shimmering shades of turquoise and light blue with opalescent hues
Elevation	Around 7,220 feet (2,200 meters)
Accessibility	Easily accessible via the Midway Geyser Basin boardwalk
Activity Status	Usually a calm hot spring; occasionally erupts slightly like a geyser
Best Viewing Time	Morning or midday when sunlight enhances the turquoise color
Trail Information	Part of the Midway Geyser Basin Loop Trail (0.8 miles round trip)
Safety Tips	Stay on the boardwalk; water is extremely hot and fragile ground surrounds the pool
Visitor Experience	Known for its tranquil beauty, opalescent colors, and close proximity to Grand Prismatic Spring
Fun Fact	The pool’s name comes from its opal-like shimmer that changes slightly with sunlight and bacterial growth

The pool’s name, “Opal,” fittingly reflects its appearance. The water shimmers with a soft mix of milky blue, white, and turquoise tones that resemble the iridescent hues of an opal gemstone. Its colors shift subtly depending on sunlight, air temperature, and microbial life along its edges, creating a living canvas that seems to change each time you visit. The steam rising from the surface often casts a dreamy veil across the surrounding landscape, enhancing its magical atmosphere.

Opal Pool is not as large as the Grand Prismatic Spring, but it is every bit as captivating in its own quiet way. The pool is roughly 20 to 30 feet across, and its temperature typically remains around 160°F (71°C), which is too hot for swimming but perfect for sustaining thermophilic microorganisms that give the pool its vivid colors. These microorganisms thrive in the harsh conditions of Yellowstone’s geothermal landscape, painting the mineral-lined edges with shades of orange, yellow, and brown.

Interestingly, Opal Pool is not always a passive hot spring. Historical observations have recorded rare instances when it behaves like a small geyser, bubbling and spouting water a few feet into the air. These events are unpredictable and short-lived, but they add an element of mystery to the site. While Opal Pool is generally calm today, the potential for change reminds visitors that Yellowstone’s geothermal system is constantly alive and evolving beneath the surface.

Access to Opal Pool is easy via the boardwalk trail that loops around the Midway Geyser Basin. Visitors can safely view the pool from designated walkways, which also offer views of nearby features such as Turquoise Pool and the massive Excelsior Crater. The boardwalk sits slightly above the springs, providing excellent photo opportunities without endangering the fragile ground. Because the basin surface is extremely thin and unstable, stepping off the path is strictly prohibited — an important safety rule that helps preserve both the environment and visitor safety.

The best time to visit Opal Pool is in the morning or late afternoon when sunlight enhances the pool’s deep opalescent colors. On cool days, the contrast between the warm steam and the crisp air makes the view even more dramatic. While Opal Pool doesn’t draw the same crowds as Grand Prismatic, this relative quietness allows travelers to appreciate its beauty in peace, making it a favorite stop for photographers and nature enthusiasts alike.

In many ways, Opal Pool represents the understated elegance of Yellowstone’s geothermal features — small but full of wonder, calm yet unpredictable, and scientifically fascinating while artistically breathtaking. For those who wish to explore beyond the park’s headline attractions, this hidden gem is an unforgettable highlight that captures the soul of Yellowstone’s thermal world.