They are aqueous solutions of ammonium phosphates and ammonium sulfates, as well as thickening agents. Most inorganic phosphates are relatively nontoxic and essential nutrients. The sodium, potassium, rubidium, caesium, and ammonium phosphates are all water-soluble. Common corrosion inhibitors added to the water are phosphates and silicates. Other chemical techniques include tests for nitrates, phosphates, sulfates, etc. Proteins can be made using nitrates, sulfates, and phosphates in the soil. This includes nitrogen compounds, water, CO, phosphates, sulphates, etc. The troilite nodules contain inclusions of chromite, sulfides, phosphates, silica and copper. Some so-called calcium phosphates contain oxide and hydroxide as well. Japanese makes traditionally use phosphates and other inhibitors, but no silicates. Phosphates and silicate, being nutrients, are typically negligible. Also mined are antimony, bauxite, chromium, gold, iron, natural phosphates, tin, and zinc. Burkina Faso's natural resources include gold, manganese, limestone, marble, phosphates, pumice, and salt. There is mining of copper, iron, manganese, gold, cassiterite (tin ore), and phosphates. It is traditionally fertilised with manure, nitrogen, phosphates, and potash.