girdle thickness

[mbn]

why does girdle thickness varies fr. thin to medium, etc. etc. why is it not uniformly thin or medium or thick?

 

[oldminer]

Diamonds are cut to conserve weight for economic reasons. Sometimes a bit of irregularity might add a small amount of retained weight. The cutter might feel this is important in some stones and less important in others. Super fine cut diamonds have pretty uniform girdles, but most diamonds have quite a variance in thickness from one place to the next.------------------
David Atlas
Accredited Gem Appraisers

 

[Garry H (Cut Nut)]

Depending on your desire to spend more for the very best, or a reasonable amount for plain best, these are the priorities you should follow on make.
pavilion angle
Crown angle
Table size
Symmetry
Girdle thickness
culet size
polish.
.
If you want all factors to be perfect then pay more, but frankly no one can tell minor discrepancies with a naked eye as you go down this list.