Warm Mineral Spring is a large, water-filled sinkhole.
The spring is surrounded by a grassy lawn and palm trees, including a few shade trees. There are chairs and picnic tables available for use.
Warm Mineral spring is large. It measures 252 ft (76.8 m) north to south and 315 ft (96 m) east to west.
There is no spring boil on the water surface. Very little aquatic vegetation or algae live in the spring.
A small, gentle spring run exits from the west side and flows southwest into the Myakka River, approximately 2.3 miles (3.7 km) away.
The bottom of the pool slopes gently to a depth of 17 ft (5.2 m) at about 40 ft (12.2 m) from the shore, before plunging to more than 230 feet deep (70m).
A rope on the water surface marks deepest section of the spring.
In the center of the spring there is a 100 ft. tall pile of debris, from when the sinkhole roof collapsed. The debris pile is shaped like a cone, and contains many ancient artifacts and extinct animal fossils.
There is an extensive underwater cave system which has been explored and mapped, including the hot spring vent which warms the spring water.
The water in Warm Mineral Springs is a constant 87 degrees F year-round.
The warm water comes from deep underground, where it’s warmed by the Earth’s geothermal heat and pressure.
Unlike other popular hot springs, the water in Warm Mineral Springs is not heated by magma or volcanic activity.
The water clarity in Warm Mineral Springs varies. It is generally yellow-greenish and slightly murky.
The water contains dozens of minerals, and contains one of the highest mineral concentrations in the entire world. Many people believe that the water has health benefits.
Visitors should be aware that the minerals, especially sulfur, will likely leave a smell on skin and bathing suit material. The mineral water can also tarnish jewelry.