what is diatomaceous earth used for??

[girls and guineas]

I have been trying to find some diatomaceous earth to buy! Today I went to Traqctor Supply and bought some food grade DE. When I opened the bag, it was gray--not white like I've seem at other breeders?? Is it supposed to be white?? What did I get?? And what can you use DE for??

 

[mnferalkitty]

mine is grey, I use mine in the feed and put some in the dust holes it is suppose to help with parasites. I also put it on the feral cat colony food to help them with internal parasites