"OK - this thread has solved a mystery for me. I inherited a little unknown thing-a-ma-bob which is about 3 inches long - didn't know what it was, but it was found in a box with some old tiny spools of thread. The previous owner was a very skilled quilter, I know that. The little bronze middle piece has Chinese characters marked on the other side. I put it with my sewing implements, thought it was a corner-pusher-outer when I used it to turn some fabric rightside out. Now I think it's a marker for the same function Tartan mentioned. One side has a flat surface, the other side, pictured, is slightly rounded. What else could it be?"
It looks like a hera marker made out of jade and silver to me.