scrollwork bakelite (?) monogram brooch

I don't know much about this. It was filthy crusty dirty when I got it, I've since cleaned it only with warm water, dish soap, and a toothbrush. It looks much better now. :-)

It looks and feels like it should be old enough to be bakelite, it weighs about 25g. Now kind of gold yellow colored if it wasn't originally, its design is deeply carved around the scroll cut initials in the middle. There is some graining to the material so I suppose it could possibly be bone but it seems too yellowed to be ivory...??? The clasp and pin seem pretty standard to me, I haven't found any markings on it.