When you hear the term “nautical jewelry,” do you picture the usual suspects, such as leaping dolphins, shells, and starfish? Maybe it’s time to think about this category again and see what’s keeping it growing.

Nautical and marine-theme jewelry is undergoing a reformation, say designers. It is no longer defined solely by traditional designs but is reaching out to include new, atypical motifs as well. It’s this variety that defines the universal appeal of nautical, a category in which few designs ever go out of style. The favorites keep on selling and the new motifs attract new customers, even in non-resort regions.

There are essentially two audiences for nautical styles, say suppliers. The biggest share of the market, of course, is in warm-weather resorts where the emphasis is on sea, sun, and fun. These include all coastal regions, with strongest sales in Florida and the Caribbean, where tourists commemorate vacations with gold charms, pendants, and earrings bearing seaworthy designs. The other audience is less typical and includes regions such as the Midwest and the Western plains, where there may not be beaches, but the appeal of the sea and its denizens has been growing. Some manufacturers also credit the category’s growth with the environmental movement.

While the overwhelming majority of nautical jewelry is lightweight 14k gold or sterling silver that retails for less than $100, there’s a growing market for upscale designs with three-dimensional forms, using 18k gold accented with pearls, diamonds, and colored gemstones. Sea creatures depicted in some of these latter pieces feature gemstone-accented eyes, pavé diamond bodies, and colorful inlays of enamel and gemstones. And as pearls continue their popularity, what better combination than a nautical design accented with pearls?

Stressing the unusual are three Florida firms: Reller & Co., where Bernard Reller combines salvaged treasure coins in nautical settings; Mercedes Franklin, which accents clusters of marine dwellers with colorful gemstones; and Designs by Slack, which goes the sporting route with three-dimensional scuba divers and wind surfers.

Scott Meyrowitz, Atlanta, creates a range of three-dimensional sea creatures in 18k gold with moving fins, legs, and flippers; New Yorker M. Latife goes inside the nautilus chambers with freeform, shell-like designs, and Californian Merry-Lee Rae lets her creativity run wild with sensuous mermaids depicted in multicolored enamel.

Today’s nautical jewelry category encompasses an ever-broadening variety of designs, with themes ranging from the traditional to the whimsical. Among the strongest nautical motifs are:

• Sea creatures such as dolphins, game fish, turtles, crabs, starfish, and seahorses.

• Boat themes, including replicas of sailing vessels as well as equipment such as anchors, ships’ wheels, dials and compasses, nautical flags, ropes, and knots. (These latter themes translate especially well into men’s bracelets and pendants.)

• Designs geared to hobbyists and sports enthusiasts, such as scuba divers, wind surfers, scuba masks and tanks, surfboards, and water skis.

• Mythical creatures such as mermaids, sea gods, sirens, and dragons.