The most versatile crystal growth technique is the solution growth. The solvent may be a substance that becomes liquid at moderately high temperature (flux). The flux growth technique is an appropriate method for materials having a high melting point, or melting incongruently or exhibiting a first-order phase transition below their melting point. Very slow cooling of the solution in an inert crucible is the most common variant of this method. The yielded crystals are separated from the residual solvent by hot centifuging in this case.