Sea salt
Salt is mostly sodium chloride (NaCl). Sea salt and mined salt may contain trace elements. Mined salt is often refined. Salt crystals are translucent and cubic in shape; they normally appear white but impurities may give them a blue or purple tinge. When dissolved in water sodium chloride separates into Na+ and Cl− ions, and the solubility is 359 grams per litre. From cold solutions, salt crystallises as the dihydrate NaCl·2H2O. Solutions of sodium chloride have very different properties from those of pure water; the freezing point is −21.12 °C (−6.02 °F) for 23.31 wt% of salt, and the boiling point of saturated salt solution is around 108.7 °C (227.7 °F).