Bastnäsit (also Bastnaesite) is the name for a group of minerals from the mineral class of "carbonates and nitrates" (formerly carbonates, nitrates and borates). All Bastnäsite crystallize in the hexagonal crystal system with the general composition (Ce, La, Nd, Y) [(F, OH) | CO3], thus contain beside the carbonate complex the metals designated as rare earth metals cerium, lanthanum, neodymium and yttrium the group of lanthanides and as additional anions fluorine or hydroxide ions. The Bastnäsite are therefore also referred to as lanthanide fluorocarbonates.