Clockwise from left: BREGUET Reine de Naples cameo watch, £46,300; CASCO loose carnelian Cowboy Skull and Pirate Skull shell cameos, €50 each; AMEDEO carnelian shell cameo hand-carved, set in 14-karat yellow gold with a base in white agate, £1,920; LYDIA COURTEILLE Rings from the Cameos and Glyptiques collection, price upon request. Clockwise from left, Breguet; CASCO; Amedeo; Lydia Courteille

CAMEOS—WEARABLE PORTRAITS carved in relief on materials like shell, lava and agate—were once known for their noble and dignified subjects: Roman emperors, queens and figures from Greek mythology.

Now, designers are giving the once-demure art form a modern twist. Leading the charge is Amedeo Scognamiglio, whose Amedeo collection stems from his family's long history of cameo making in Torre del Greco, Naples. Alongside more traditional offerings, monkeys, skulls and crossbones and jaunty cameo cuffs also make an appearance, each piece still handmade.

Casco, a nearby factory run by another branch of the Scognamiglio family, has its own range of classic pieces and also makes skull cameos for a number of contemporary fashion designers.

One big jewelry brand keeping the tradition alive is Breguet, which employs cameo makers in Naples to make both watches and jewelry. Breguet's intricate Reine de Naples cameo watch has a sunflower delicately carved from shell as its center. Its Rose de la Reine jewelry range centers around a cameo engraved rosebud, mounted on precious stones or Akoya pearls.

For an interesting twist, Parisian jeweler Lydia Courteille takes old cameos and reworks them into modern pieces, using jewels such as black diamonds, green garnets and black rhodium gold. Her rings are showstoppers.