Diatomaceous earth is used as an insecticide, due to its abrasive and physico-sorptive properties. The fine powder absorbs lipids from the waxy outer layer of insects’ exoskeletons, causing them to dehydrate. Arthropods die as a result of the water pressure deficiency, based on Fick’s law of diffusion. This also works against gastropods and is commonly employed in gardening to defeat slugs. However, since slugs inhabit humid environments, efficacy is very low. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Diatomaceous earth is also a good source of silica containing around 80%.