He starts by taking a really small piece of diamond (not enough to cast Resurrection), and casts major creation to make 15 cubic feet of diamond. I estimate that this diamond would be worth more than 10,000gp. This diamond will last 150 minutes, which is more than is necessary to pulverize it into diamond powder and cast resurrection, using the created dust as component.
Is there something in this process that shouldn't work?
I am asking for RAW. I know this could be easily patched, which is what I expect my GM to do, but am curious about the rules.