Given what i'm reading/learning about what the value of a ruby and/or sapphire may or may not be
I'm thinking the 4 "C's" (as with diamonds) come into play...
Cut, Clarity, Color, and Carat.
Some differences on what people believe the 5th "C" to be, ie "Cost" or "Confidence" or "Certificate"
The 5 C's is one of the first things a wannabe groom learns as he embarks on his journey into the unknown...been there done that!