Grip Material question

[velocette]

Have an FN .25 acp pistol from an estate. Pistol is in very nice condition with no rust or damage.
It has some aftermarket grips of unknown material. Any guesses or knowledgeable guesses as to what they are? Right grip has a stain from the brass fastener on the holster it was kept in.

 

[CapnMac]

Will guess that's bone.
Bovine femur makes a good "blank" for stock or scale making.

 

[Archie]

I think the Cap'n is on the right track.
The grain is wrong for ivory. Also wrong for wood. However there is a 'growth pattern' suggesting organic and not a plant. Not plastic, either. Doesn't appear to be stag horn - they took off all the good looking stuff. I've never to my knowledge really examined bone. Not sure I've even had a passing glance. But it seems as the Cap'n posits.