Question

what is the reason for the diamond shining and how is it appreciating..?

Answer 1

The sparkling isn't just the high refractive index - the shape matterstoo. Diamonds are cut so that a light ray falling on the diamond is reflected multiple times inside the diamond and therefore sends light out in all directions. Actually, diamonds don't shine, they reflect.

Answer 2

First of all, Diamonds won't shine,they reflect.So,this happens through a phenomenon known as refractive index.It has high refractive index i.e.2.42.If a light Ray enters a diamond it is very likely to undergo total internal reflection which makes the diamond shine.And also due to low critical angle(24 .4°)the diamond shines

Hope this helps you quickly