Sadly do the the economic climate I am stuck working at a feed store even though I have 2 college degrees in the the tech field. "Real Salt", mentioned earlier is mined in Redmond Utah from a deposit from an anient sea bed. The stuff comes out of the ground in chunks like rocks, damn near as hard too. They sell big chunks of it for livestock use and grind it up for human consumpion. I started using it about a year ago thanks to the employee discount. The stuff is great, I will neve use Iodized table salt again given the choice. Do to its source it has somthing like 70 trace minerals in it and no crap. But you also pay for thier marketing which will be obvious when you see the price compared to to the table salt you buy in the store.
As far as other salts, a solar mixing salt is about the closest you will find to pure sodium choride. It can be had from any feed/farm store in 50# bags, just ask for mixing salt and you will get exactly that. As far as the blocks I would highly argue against using them for anything but livestock. They come in all flavors, cobalt, sulfer, iodized, trace mineral, trace mineral w/ selenium, and the list goes on. Just a plain white salt block is simply that, just salt. But try doing anything with a 50# block of salt. 50# of salt is heavier than 50# of anything else. If you want to argue with that statment try dealing with one for very long and you will see what I mean. Add to that even though they look like it, they are not square and don't stack that well. I would not be afraid to bust a piece off of one and use it if I was in need of salt but it would not be my first choice.
