Thought of that too but, there is no guarantee that somebody will buy that item. However if you can put diamonds on "the market", the odds are it will sell - everybody needs diamonds, especially for premium since it's really worth it.
I've played other browsergames too and I know that more than 95% of the ideas are being declined but I feel this one is pretty good since it will really help people. If you have a poll - agree/disagree, I bet that the generality will like the idea.
