I first heard about "sel gris", literally "salt gray" in french several years ago as that is what chef Michael Chiarello uses, liberally. His show "Napa Style" started out on FoodTV and now has moved over to the Fine Living Network. Its good viewing though at times his parties in the vineyard are so far fetched for us regular folks.
I've sorta half-assedly look for the stuff and stumbled across a jar of "Sel Gris aux Herbes" at Surfas a while back. (Literally Salt Gray with Herbs.) I grabbed a jar a few weeks back and only recently decided to crack it open and wow...what a different level of flavor it brings.
I used it with some vegies I sauteed to put with some couscous. The "Sel Gris" was tossed on the hot veg just before I added it to the cooked couscous and folded it in. Wow. Just plain old wow. Yes you got little bits of salt that just exploded with herbal goodness and a "sweet" finish.
Next experiment is on some Sourdough bread I am baking at the moment.
Doing a little research I found out that "Sel Gris" is actually a very healthy salt. It gets it dark gray color due to the high mineral content in the salt. Those trace minerals also are what we need in our diet. Getting them naturally has to be way better for us than getting white salt that has been "iodized". Am not an expert but that is my take on what I've read. If I'm wrong then I may have kicked off a good urban legend.
If you can't find it locally you can always order your own stash at Surfas Online.
ps...you will be allowed to use a good kosher salt for general baking, cooking and pickling, sea salts are way too expensive to use for the general stuff, they are a finishing salt.