Metals that are perceived to have high supply risks have recently been called "critical metals". The exact list of metals that are considered to be critical varies, but typically include indium, gallium, germanium, selenium, tellurium, neodymium, dysprosium, lithium, vanadium, tin, tungsten, molybdenum, rhenium, tantalum, niobium, cobalt and the PGE. The mission of the IAGOD Working Group for Critical Metals is to promote and coordinate research into the mechanisms that lead to economic concentration of critical metals in geological environments