Crystallisation is a separation technique that is used to separate
a solid that has dissolved in a liquid and made a solution.
The solution is warmed in an open container,
allowing the solvent to evaporate, leaving a saturated solution.
A solution that has as much solid dissolved in it
as it can possibly contain is called a saturated solution.
As the saturated solution is allowed to cool,
the solid will come out of the solution and crystals will start to grow.
The crystals can then be collected and allowed to dry.