I got this chip several months ago but can't remember where. Likely either the Convention or eBay. Can you read the monogram? I see the A, and maybe an intertwined R, but the intertwined swooping curve on the right doesnt' look like a letter.

The material is polished and has a grain to it, and is probably bone. Edges are rounded. There's a serial number, so this is probably from a club somewhere. Size is about 38 mm.