2 Answers

http://www.differencebetween.net/object/comparisons-of-food-items/difference-between-kosher-salt-and-sea-salt/

Kosher salt and sea salt are most often used for cooking and cosmetics. Though both the salts are obtained by the evaporation of seawater, kosher salt and sea salt are different in many ways.

Both kosher salt and sea salt consist of about 97 per cent sodium chloride. The main difference is the addition of various minerals to these salts. Where kosher salt has no additives, sea salt has certain additives that make it different. Magnesium and calcium are added to sea salt, and this gives it a different taste, a taste that is different from kosher salt.

Kosher salt is unrefined salt, whereas sea salt is refined. Kosher salt can be called pure sodium chloride, whereas sea salt is sodium chloride with additives. While sea salt has added nutrition, kosher salt has no additional nutrition.

When comparing the crystals, kosher salt come in bigger crystals when compared to sea salt. Kosher salt has a flat platelet shape, whereas sea salt has more pyramid shaped crystals. Kosher salts also have a larger surface area in comparison with sea salt. Well, kosher salt also occupies more space than sea salt.

Another difference that can be seen is that the kosher salts absorb more moisture than the sea salt. Well, kosher salt is widely preferred for curing meats than the sea salts.

When comparing kosher salt and sea salt, the former one mentioned, dissolves more slowly.

When comparing the price, sea salt is more expensive than kosher salt because of the difference in their preparation.

Seriously, None at all.  ALL salt is derived from the sea and is indistiguishable.  "Labels" sell for more money.  Salt is salt. A basic of life.