Celluloid most likely. Its out gassing too from the looks of it...‘77 faux mother of pearl. What would the scales be made of? Acrylic? I bought it off a guy for something like $20. The bolsters are road rashed, as was the same side scale. I took some 400gt & then some 1000gt. The springs are nice and tight, nice walk and talk. Just a nice little 5th pocket user. View attachment 2642929