Yes, Alligator, no a stone, no bone, no crystal, no glass... Alligator "skin" part of it at leas, skin from its back where you can see the tiny bones that create that almost dinosauric look our aquatic fellows have. Set as a stone on a classic copper setting, AlliGator has a small blue stone as a color splash -no pun intended? Or maybe intended? ;)- resemblance from the glades and the water where he came from. 
Mean tribal, barbaric brutalist, postapo perhaps? Industrial organic? I do't know, but fun and unusual for sure.
OOAK it measures total 102 x 61mm approx.