When hard-shelled algae called diatoms fossilize, they create a sedimentary rock that is easy to crumble called diatomaceous earth. According to the National Pesticide Information Center, diatomaceous earth makes up 26 percent of the earth's crust by weight.
What do we like about it? It ticks off all our boxes: it's natural, it's easy to use, has multiple uses, it doesn't cause cancer (unless you stick your nose in it and breathe in for one hour every day - but that's the case for any powdery substance that you breathe in for long periods of time) and, as far as we can tell, it isn't being over-exploited.
In some places, it can be hard to buy diatomaceous earth in small packages, so we've lined up 7 ideas for using it at home.