Bischofite is a natural mineral which is a type of magnesium chloride. Some synonyms for bischofite include magnesium chloride hexahydrate, magnesium oil, and nigari. Magnesium chloride hexahydrate is commonly used for medicinal purposes to treat conditions such as sore muscles and joint pain. Nigari is a form of bischofite that is commonly used in the production of tofu. It is also used to soften hard water, and as a natural remedy for a variety of health conditions. Magnesium oil is a popular name for bischofite because of its high concentration of magnesium chloride which makes it an effective and natural remedy for a range of ailments.