Reading through some claims online impurities do account for a slight difference in sodium content. The thing that gets cited for major differences is volumetric comparisons. Sea salt and coarse rock salt usually have bigger chunks than table salt, so less fits in a spoon. Therefore every spoon of a coarse salt has substantially less sodium …and substantially less salt flavor when dissolved.
Reading through some claims online impurities do account for a slight difference in sodium content. The thing that gets cited for major differences is volumetric comparisons. Sea salt and coarse rock salt usually have bigger chunks than table salt, so less fits in a spoon. Therefore every spoon of a coarse salt has substantially less sodium …and substantially less salt flavor when dissolved.