The history of salt in Italy is long, stretching from the ancient salt roads over Liguria's Maritime Alps to centuries of politicking and battles, taxes and state monopolies (you'll still see it listed on old tobacconist signs). These days, however, you can just buy it in the supermarket.
fior di sale or fiore di sale is unwashed, hand-harvested and untreated, the 'flower of salt' is moister and has larger crystals than typical table salt, and is rich in potassium and magnesium. And it's much pricer as well.
In Italy, much of it comes from the historic salt pans by Trapani. In trendy Italian restaurants, you'll often see the French version, fiore di sale di Camargue (France).
Two kinds of sea salt harvested the traditional way, from Cervia (Emilia-Romagna) and from Trapani (Sicily) are in the Slow Food Presidium. The salt from Salsomaggiore Terme, sourced from its many underground salt wells, was recently made DOC.
salgemma: rock salt Otherwise known as halite.
senza sale: salt free
Image by Algor7, Creative Commons License