Al
The stones you mention have a lower RI (refractive Index) than diamond
Garnet depending on what type 1.69---1.87
Emerald 1.57-1.58
Ruby 1.76-1.77
spinel1.71-1.73
zircon 1.93-1.97
Diamond 2.42
SteveH
A claw mount dosent have to be like the wifes engagement ring it can wbe quite strong.I you drilled and ground away half of the cicumfrence leaving 4 claws of steel not gold allowing light to get at the facets below the girdle of the stone
The only only front sight I have ever had damaged was when the Lepold bit the bloody thing of and I couldn't get a bead on him so I had to kill him with my knife
good shooting
sbs470