I wouldn't take it. It's been a folk remedy for 100s of years. However the very properties that make people take it internally as a 'detox' is the very reason not to use it. It holds on heavy metals, dioxyins, pesticides etc..etc.
So, if its exposed to any type of run-off water (which almost everything is that's mined) it will concentrated those poisons. Probably fine for mud mask tho, or chicken pox, poison ivy etc.

Food52 is not part of Whole Foods. You should ask this kind of question in the store.
Look for Now Brand for a good bentonite -- and of course there other good ones.

A store that sells winemaking supplies should have food-grade bentonite. Might find it, too, at "health food" stores. And, of course, like most products these days, it is available online.

The store her in Indianapolis used to in the bulk spice section. If you are wanting it to clarify something, like wine or cider, you can go to a homebrew store they will have it, or should.