What is total internal reflection?

To understand total internal

How do you evaluate a gemstone?

There are various methods to evaluate gemstones.  Here is a gemstone framework guide to abide by:

What you look in any particular gemstone is beauty, rarity, durability to contribute to its desirability.

An example would be:

Identification - Natural Untreated Ruby
Weight - 32.08 Ct.
Shape - Cushion
Treatment- None
Dimension - Not Available
Color - Pigeon Blood
Luster - Bright
Wear - Minimal
Damage - None
Faceting - Faceted
Transparencies - Exceptional
Optical Effects - None
Certification -
Valuation - $6,736,750
Country of Origin - Burmese
Provenance - Chaumet