Answer the following questions:
The refractive index of diamond is much greater than that of ordinary glass. Is this fact of some use to a diamond cutter?

Refractive index of diamond is nearly 2.42 which is much larger than that of ordinary glass (nearly 1.5). The critical angle for diamond is nearly 24° and, is less than the critical angle of glass. A skilled diamond cutter exploits the large range of angles of incidence in the diamond (24° to 90°), to ensure that light entering the diamond is totally reflected from many faces before getting out. This produces brilliant sparkling effect in the diamond.