prevent their spontaneous precipitation into calcium carbonate. Double salts Double salts containing magnesium sulfate exist. There are several known as sodium magnesium sulfates and potassium magnesium sulfates. A mixed copper-magnesium sulfate heptahydrate was recently found to occur in mine tailings and has been given the mineral name alpersite. Research Research on topical magnesium (for example epsom salt baths) is very limited. The Epsom Salt Council recommends bathing 2 or 3 times/ week, using 500-600g Epsom salts each time. See also Calcium sulfate Magnesium chloride References External links International Chemical Safety Cards—Magnesium Sulfate Desiccants Laxatives Magnesium compounds Sulfates