I thought it was coarse salt just double checking I usually have it in the house but you know how it goes when you need it you're out

How about Black Lava Salt. With crushed orange zest (lime would be redundant) adhered with lime juice on the rim of the glass.

I think experimenting with different salts would be an awesome experiment!

Riffing on Sam1148's salt combo suggestions, in Mexico, they rim the little shot glasses for mezcal with cayenne pepper and salt - as if mescal doesn't supply enough fire on its own.

I'm a big fan of a product called "True Lime". http://www.truelemon.com/true-lime.html
A crystallized lime product. It mixes well with salt.

I'll grind kosher salt into powder in a coffee grinder and mix that with salt, garlic, ginger powder, paprika, white pepper. To use on popcorn when it's ground into dust.

Or mix with Kosher salt for salting the rim on Margarita with out grinding.

Off topic here...but Sriracha Salt is great for bloody marys. As is the lime powder/kosher salt combo.
Easy to make at home.
http://www.food52.com/recipes/11404_sriracha_salt

a drop of food coloring rubbed into salt?? what do those neon colored ones retail for?

Ditto. A long. long time ago, someone I continue to live with bought a little plastic tub labeled "Margarita Salt." It looked and tasted just like Diamond Crystal but cost 10x as much. I put my hefty $2 box next to his puny $2 tub and told him that if he continued to buy expensive salt, I'd start buying cheap tequila.

Have you seen the neon-colored salts? I love the bright colors and thought about making my own, but then I worried about the effects on the big guy's moustache. Maybe for next April 1.

kosher salt as obleaki says, it clings well to the rim of the glass

Diamond Crystal kosher salt.