Question

why does a diamond shine more than a glass piece cut to the same shape?

Answer 1

THE reason is that Diamond is a crystalline solidstructure of the atoms and molocules that make it up. when light passes though it it becomes reflected by the many internal surfaces and can also be split into different colors like a rainbow.

A glass crystal is generaly a simple glass with a constituant of lead which gives the glass its attractive appearance. There is no internal cristalline structure in glass so only reflections can occur when the light is reflected on an opposite surface.

Reason also occurs due refructive index.

Answer 2

Diamond has more refractive index than glass,its refractive index is 2.54 whereas refractive index of glass is 1.5 only. When light enters it , and incidents one of its side at critical angle , then it reflects it back into the same medium ,this phenomenon of reflecting back light in same medium is called Total internal reflection, this happens many times leading to its shining whereas Total internal reflection doesnot takes place in glass due to less refractive index.