From the Manufacturer's Label:
Our Magnesium Oil is harvested through Solar Evaporation from Utah's ancient inland sea, the Great Salt Lake, which is naturally high in Ionic Magnesium Chloride. White Egret Pure Magnesium Oil leaves less residue and contains no heavy metals. There is approximately 12,000 mg of Magnesium Chloride contained in this one bottle. 20 sprays will deliver approximately 250 mg of elemental Magnesium to help beautify the skin. This product also includes 72 ionic sea minerals in a completely natural balanced solution.