I like the idea. I'm not sure that it's really too powerful to work (but see my pricing note later). By the time you have Provinces, making this thing worth $4, you probably won't get the chance to play it very many times. Very interesting with Peddler, by the way.
If you wanted to nerf it a bit, only discard the revealed card IF it's a victory card. Then you can keep your Gold, as you probably should, but 4xJewels+Province won't get you to $16, as it probably shouldn't.
The cost might need to go to as high as $5, though. Reasoning: You wouldn't buy it anyway until after the first shuffle, which means you wouldn't use it until after the second shuffle, and at that point I suspect you would be very unlucky indeed not to be able to make it worth at least a Silver. So I suspect it will basically always be worth at least $2, with the potential to go up to $3 and $4 in the late-game. That's similar to the range of value you can squeeze out of Venture. Not quite as good, perhaps, but I suspect I'd usually prefer Jewels to Royal Seal and Stash.