Explanation:

 In the West Bengal, Birbhum is the vital supply center. Here, the china clay mines are found in Kharia, Mocdam Nagar, Komarpur, Angargaria, Md. Bazar. China clay is fine white clay resulting from the alteration of feldspars. It is unique industrial mineral and it is known for its low velocity, low plasticity, non abrasiveness, good brightness and opacity and low hit and electric conductivity.