Coprecipitation occurs when a solution (vapor) is supersaturated with the substance forming the precipitate or when a melt is supercooled. Coprecipitation begins only at the conclusion of a latent period. The length of this period can be prolonged from microseconds to tens of hours by altering the degree of supersaturation (supercooling), the degree of mixing, and the purity and temperature of the medium from which the precipitate separates.