I was discussing this with some friends yesterday, and we’ve basically narrowed it down to three contenders. In order:

1. Salt
2. Ice
3. Copper ore

Rules:

Going by dictionary definition of “rock”, which means “stone”, which means “mineral”.

Water is a mineral according to the dictionary, which is why ice is in there.

Minerals are inorganic according to the dictionary, so things like sugar crystals don’t count, since they’re organic.

So, is it one of those three, or are there other delicious rocks that we’ve overlooked?