Is Matter Around Us Pure ? — Science STD 9 — Question

Crystallisation is the process of slow precipitation of solid crystals of a substance from a concentrated homogeneous solution. It is basically a separation method in which a substance is transferred from the liquid (i.e. solution) phase to the solid state. Thus during crystallisation, the substance is obtained in pure crystalline form in china dish which has no impurity. 
When formation of crystals take place in china dish, we observe that all crystals of different compounds looks different. Some crystals are needle shaped, some are cube shaped and some are hair like which are extremely fine. There are many different forms of crystals. You will learn about them in higher grades.