I have one like it also, its worth keeping but no real value, Actually I have several, caused by like they say grease filled, as a liquid does not compress, you will be able to see the outline, with the lighting, and angle just rite, some call it phantom missing. its just grease, debris in the die. pretty common, they try to get a lot of money for them on ebay. but worthless to a collector. I collect the worthless ones. lol