Nice lamp, I was thinking you could also use oyster shells as you often find these washed up on the beaches and they can be pretty large. I made a really good lamp by pecking out a big chunk of red sandstone that I found on a shingle beach, into a fairly nice sized bowl. I used sunflower oil for the fuel and the chunks from the tube layer of a polypore fungus (think it was ganoderma applanatum) for the wick. The tube layer of polypore fungi makes an EXCELLENT wick because the hollow structure of the tubes. You should try it!