The figures looked more or less human. And they were engaged in religion. You could tell by the knives (it’s not murder if you do it for a god).
—(Terry Pratchett, Small Gods)
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.