Stone ? Real or synthetic? What type ?

I like those a lot! The look is great, but I wonder how they will behave in the field (if that is their eventual destination). It would seem that stone may get pretty cold in the winter; that's not something I'd like to experience when gutting a deer. Either way, the craftsmanship on shaping and polishing of the handles is worth the price of admission!

I don't know about these, but Jay Fisher makes a lot of knives with gemstone handles and explains why here.

He made a gemstone-handled knife for my wife and I have an ironwood-handled skinner he made.