Question

diamond shines brightly but the piece of glass dont why please briefly clear it

Answer 1

Actually the secret that's rattling inside the diamond is refraction, total internal reflection and dispersion. the refractive index of diamond is pretty high and is also dispersive . due to this diamond shines brightly

Answer 2

Answer:

so, in the diamond total internal reflection takes place while in the glass piece cut to the same shape are less prone to have total internal reflection. Thus, due to this reason of more total internal reflection of the diamond than the glass the diamond shines more than a glass piece cut to the same shape.