Crab shell is iden-tified as a composite structure having three separate layers. Topmost layer is called as epicuticle which is a nonchitin surface vainermainly for the protection of the crab shell surface. Second and thirdlayers are together called as procuticle. The topmost layer of theprocuticle is identified as exocuticle and the bottom layer is referredto as endocuticle. Both these layers mainly consist of calcite crys-tals which are bound together by a complex matrix of chitin andprotein fibers. The striking feature of this fiber matrix is that theyshow twisted plywood pattern, which is commonly referred to asBouligand pattern. Individual fiber has a thickness of approximately60–70 nm which can be further divided to even smaller nanofibershaving diameters approximately 3–5 nm