The Dead Sea seawater has a density of 1.240 kg/L, which makes swimming similar to floating."
dead seas near Jerusalem
halite phenomenon (from wikipedia):
"commonly known as rock salt, is the mineral form of sodium chloride (NaCl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides, and borates"