Apollo GDS Training Books. Description: This book is an integral part of the Introduction to Apollo course. Each chapter corresponds to an online lesson and contains a lesson summary, review questions, emulator exercises, format lists and in some cases supplementary entries not taught in the online lesson.
One source of sea salt is brine, with the salt being produced through evaporation. Table salt can also be produced from rock salt, in which case evaporation is not necessary for processing. The salt crystals are processed to remove any impurities that may be present and allowed to recrystallize.
Salt is a mineral composed of sodium and chlorine. Neither can exist alone in natural form. Together, they form the chemical compound that is sodium chloride. To geologists, salt is known as halite. Salt is a crystal of the isometric system, meaning it is usually cubic and perfectly symmetrical. Pure salt crystals are colorless, although a pile of them will appear to be white. Impurities in the crystals may cause salt to be various shades of yellow, red, blue or purple.