No, it is not like cat litter at all.
"Diatomaceous earth, diatomite or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 3 μm to more than 1 mm, but typically 10 to 200 μm.
Wikipedia"
Another source but from an academic university website, "
What is diatomaceous earth?
Diatomaceous earth is made from the fossilized remains of tiny, aquatic organisms called diatoms. Their skeletons are made of a natural substance called silica. Over a long period of time, diatoms accumulated in the sediment of rivers, streams, lakes, and oceans."
This comes in a very fine powder already and you should DEFINITELY be wearing a mask when doing this. You can buy food grade DE or you can get some at feed stores where farmers will use it for the storage of their various grain feeds. They mix it with their feed to keep it clean from insects. Perfectly safe for animals to ingest it when prepare in this way. That is the cheapest option. I buy 25 lb bags at a time and it is cheap! I spread it around my entire garden. Works great but it breaks down quickly with water or mist so reapplication is needed when you see it has been rinsed away.