Diamagnetism is a basic property of all matter, though it is generally very weak. It is due to the no cooperative behaviour of oepenrbiting electrons when exposed to an applied magnetic field. Diamagnetic substances consist of atoms which have no net magnetic moments. (Each and every orbital shell is filled and there are no unpaired electrons). When a diamagnetic substance such as a silicon crystal is placed in a magnetic field, the magnetization vector M in the materials in the opposite direction to the applied field. Hence the resulting field B within the material is less than μ0H. Therefore the susceptibility is negative. The negative susceptibility can be interpreted as the diamagnetic substance trying to expel the applied field from the material. When a diamagnetic specimen in placed in a no uniform magnetic field, the magnetization M of the material is in opposite direction to B and the specimen experiences a net force toward smaller fields, as dedicated. Put a note that when the field is zero then the magnetization is zero. The other characteristic behaviour of diamagnetic materials is that the susceptibility is temperature independent some well known diamagnetic substances are quartz calcite, water, copper, silver, gold, etc.