“ Village has a nearby natural substance that comes from the ground and burns well when lit. They use it only locally and try not to let the secret get out.”
“ A new substance is found in an out of the way area and kept very quiet. It is found to make a perfect counterfeit diamond. Only the most expert of expert appraisers would even have a hope of noticing that it is fake. Only one problem: if it gets wet it starts to slime and if it is saturated, it turns into a glob of gel.”