Miscibility is the ability of two or more substances to mix, and form a single homogeneous phase. When two substances are immiscible they will form separate phases when mixed; the best known example is oil and water. On the other hand, water and ethanol are miscible in all proportions, and some combinations of substances are only somewhat miscible; for example, adding more than a certain amount of table salt to water will leave some in the solid phase, though this is more properly a solution, one specific type of mixture.