The unusual hue is caused by deposits of sulphur and ferrous (iron) salts that rise to the surface and reflect light. The water is highly acidic, with a pH of approximately 2, and emits a pungent "rotten egg" smell due to hydrogen sulphide gases.
In the geothermal wonderland of near Rotorua, New Zealand, the Devil's Bath (Māori: Roto Karikitea ) is a world-renowned natural attraction. the devils bath
The pool is famous for its striking neon-green colour, which can shift from soft lime to a vivid "radioactive" yellow depending on the sunlight and cloud cover. The unusual hue is caused by deposits of