It would be hard to find a food as closely tied to the growth and development of society as salt. During the Roman Empire, the Sicilian salt flats at Trapani contributed so much to the local economy that the word "salary" is derived from it. The demand for salt, not only as a flavor-enhancer but as a preservative, led to the cultivation of trade routes throughout Europe and Asia.

Until the industrial age, salt was a regional foodstuff, mined or produced from nearby seawater, and it retained trace minerals and other characteristics unique to the source. Industrialization changed that: Salt became cheap, uniform, and widely available, thanks in no small part to the Morton Salt Company. Formed in 1910, the company's innovations of adding anti-caking agents and iodide to salt—not to mention its distinctive blue cartons—made salt the first mass-market fortified food.

Today, salt's fortunes have shifted yet again. Connoisseurs claim additives give table salt a bitter, chemical flavor. So they are seeking out regional, hand-harvested specialty salts that come in a kaleidoscope of shapes and colors. The retail and restaurant worlds have taken notice.

Thomas Keller's Per Se in New York presents a tray of 10 different salts to diners, while the restaurant Cyrus in Healdsburg, California, has both Maldon sea salt and pink Hawaiian salt on its tables for diners to experiment with. Salt-centric boutique the Meadow in Portland, Oregon, has 85 to 90 different salts at any given time, according to co-owner and self-described "selmelier" Mark Bitterman. "We've doubled in size every year since we started in 2003, but I think we've just hit the tip of the iceberg," says Naomi Novotny, vice president of specialty salt purveyor SaltWorks.

Fortunately, you don't need a pile of knowledge to be—ahem—judged worth your salt. Just use these mouthwatering tips.

Colored Gems Though we think of salt as characteristically white, it can also come in pink, red, black, gray, and brown, primarily due to small amounts of different minerals. Along with the varying shades come nuances of flavor. Pink Himalayan salt, which contains dozens of minerals, has a less "salty" profile. Black Hawaiian and Red Alaea salt (also from Hawaii) contain tiny amounts of activated charcoal and red alcea clay, respectively, which contribute an earthy flavor. Amar Santana, executive chef of Charlie Palmer South Coast Plaza in Costa Mesa, California, started using black salt for its looks, then got hooked on the taste. "It has a nice crunchy texture and it's not as overpowering as regular salt," he says. "It tastes fresh, like the ocean."

Kosher Qualities Kosher salt is a favorite among chefs because of its clean, straightforward flavor profile. It gets its name not because of any special taste or even because it falls within Jewish dietary law. Its large crystals were traditionally used to draw the blood out of meat, one of the steps involved in making meat Kosher.

Squares and Flakes The shape of a salt affects the taste and perceived saltiness. Commercial salt is made up of cubic crystals, which dissolve more slowly for lingering flavor. Flake salts, such as those from the Maldon area of the U.K. and the Murray River in Australia, dissolve quickly, giving anything they're sprinkled with a shot of flavor that fades fast. These kinds of salt are generally labeled as flake salts on the packaging.