There are many different specialty salt products available that are used in gourmet cooking to enhance the flavors and finish of foods. Some of these include:

black salt - an unrefined mineral salt that actually is pinkish-gray in color and has a strong, sulfuric flavor
Used in authentic Indian cooking.

coarse salt - a larger grain sea salt crystal that is often used to crust meats or fish and for flavoring in stews, soups, and pastas

Fleur de Sel - a hand harvested sea salt that is very fine and on the more expensive side because of it's rarity; traditional French Fleur de Sel is collected off the coast of Brittany
Ideally used in: salads, cooked vegetables, and grilled meats.

grey salt - also known as "Celtic salt" - a naturally moist sea salt that is grey in color because of its high mineral content; is also found on the coasts of France

Kosher salt - used in the preparation of meat according to the Jewish dietary guidelines; contains fewer additives and has a more salty taste than ordinary table salt; comes in flake form, rather than granules
Other common uses: to top pretzels, rim margarita glasses

smoked sea salt - a relatively new gourmet salt; is naturally smoked over real wood fires to infuse the salt with a smokey flavor, which gives food a unique flavor
Uses: grilling or roasting, on seafood such as salmon, soups, salads, pastas, and sandwiches