Crystals are solids that form by a regular repeated pattern of molecules connecting together. In some solids, the arrangements of the building blocks (atoms and molecules) can be random or very different throughout the material. In crystals, however, a collections of atoms called the Unit Cell is repeated in exactly the same arrangement over and over throughout the entire material Because of this repetitive nature, crystals can take on strange and interesting looking forms, natu


They have 3-D, orderly arrangement of atoms, molecules and ionsĀ 
they have sharp melting points.
crystalline on breaking we get neat or clear surfaces.
they are isomorphic.
Those solids whose constituent particles i.e. atoms, molecules, ions are present in regular 3 dimensional i.e. 3D arrangement are called Crystalline solids.