I'm no silver stacker, but I think the yellow is probably gold. The below is a 2oz version you can get from the Perth Mint in Australia (the back of your coin gave it away), and they have all sorts of fantastic 'extras' embedded on their coins. See the image below - they seem to have actually printed the rabbits on this one.
Either way, I don't think it's something you need to get rid of.
Ha ha, Yes, it is gold! It was my lame attempt at a joke which seems to have spectaculary backfired...
I thought it may have been a joke, but everyone was commenting so seriously, I started to question my own take on it.
Yeah, I was a bit surprised as well! I guess that goes to show how lame my joke was... my wife even said it was a dumb joke...