I suspect the inlays are probably "capiz" shell - which is a commercial name for the "windowpane oyster", Placuna placenta. This shell is widely used for all kinds of craft and inlay work. The shell is off-white with a slight silvery luster, and is translucent. They also dye them, so if your inlays are colored, they may be dyed capiz. Paul Monfils Rhode Island