9 Amazing Facts About The Blue Lagoon - #6 Will Shock Even Icelanders!

FrostedHarbor Updated: 2025-07-30

2. The Science Behind the Blue

The distinctive milky-blue hue of the Blue Lagoon is not only aesthetically pleasing but also a remarkable scientific phenomena that still fascinates both scientists and guests. Three active components—silica, algae, and minerals— abound in the water. The way silica reflects sunlight determines the ethereal blue hue; the white silica mud at the bottom accentuates this effect and produces an amazing interaction of light and colour. With more than 50 distinct minerals in the water, its special mix produces a complex biosphere that keeps its own delicate equilibrium. Surprisingly, year-round the water temperature always falls between 37 and 40°C (98-104°F), independent of Iceland's sometimes hostile and erratic climate. The constant flow of geothermal water, refreshed every 48 hours, guarantees that the lagoon stays fresh and clean and accounts for its persistent warmth. After much research on this amazing natural occurrence, scientists have found that the particular mix of minerals and the ideal pH level produces an environment where dangerous germs cannot flourish, hence naturally clean and safe for swimming. This self-sustaining ecosystem is a living laboratory for scientists investigating geothermal activity and its possible uses since it is evidence of the complex balance of nature.