Geology and Minerals
Hard water is water with a high mineral content (in contrast to "soft water"). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum, which are largely made up of calcium and magnesium carbonates, bicarbonates and sulfates. Drinking hard water may have moderate health benefits due to the mineral content. It can pose critical problems in industrial settings, where water hardness is monitored to prevent limescaling in boilers, cooling towers, and other water-handling equipment. In domestic settings, hard water is often indicated by a lack of foam formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects.
Atakor volcanic field.
Lakes on Mars.
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