Why does light move way slower than normal within a well cut diamond???

Answer 1

This is because light travels slower in optically denser medium.
From Snell's Law, i.e., second law of refraction of light, it can be shown that, when light travels from optically rarer to optically denser media (air to diamond in this case), the velocity of light varies inversely to Absolute Refractive Index of the medium (with respect to vacuum or air).
If C and C' be the respective velocities of light in vacuum and diamond, then C/C' = U'/U, where U' and U are the absolute refractive index of diamond and vacuum.
Now U=1 when medium is air. So, C' = C/U'. As U' is > 1 for diamond, so C' is < C.
Since the Refractive Index of diamond is about 2.417, the velocity of light is 2.4 times less in diamond.
A well cut diamond has many faces from which light rays get reflected (by a phenomenon known as total internal reflection) causing sparkling of diamond.

Answer 2

thats what diamonds are 4 thats why your supposed to weare them because if you are somewhere social someone will notice your ring before they notice where they saw you so they can talk to you