The top prize winner at the 2010 International Pearl Design Competition and now a resident of the Smithsonian in Washington, DC, the "South Sea Glow Necklace" provides beautiful examples of June's birthstone.

The piece, which features three golden South Sea cultured pearls and two white Akoya cultured pearls (ranging in size from 4.5mm to 11.5mm), was hand fabricated by designer Adam Neeley utilizing special gold alloy that transitions gradually from pure 24-karat yellow gold at the bottom into a cool white gold at the top. The gold to white precious-metal transition aligns neatly with the designer's choice of pearl hues.

The South Sea Glow Necklace won the President's Trophy (the top honor) at the Cultured Pearl Association of America's annual contest in 2010 and was subsequently donated by the designer to the Smithsonian National Gem Collection in 2012.

One of June’s three official gemstones, the pearl is unique among all of the gems because it is the only one formed entirely within a living creature.

Natural pearls occur when an irritant enters the oyster’s shell. To protect itself from the foreign body, the mollusk secretes layers of nacre, which, over time, become a lustrous pearl. To make a cultured pearl, a shell bead is surgically implanted into the mollusk to induce nacre production.

South Sea pearls and Akoya pearls are similar in that both varieties are cultivated in salt water.

Akoya pearls come mostly from Japan and range in size from 2 mm to 10.5 mm. They are usually white or cream in color and round in shape.

South Sea pearls originate in Australia, Indonesia and the Philippines, and can range in size from 9 mm to 20 mm. They can be white, cream or golden in color.

According to the American Gem Society, Tahitian pearls are interestingly not exclusively from Tahiti – they’re grown throughout several of the islands of French Polynesia, including Tahiti.

The greenish-black varieties of Tahitian pearls (known as peacock green) are the most coveted, but colors can include varying shades of gray, blue, green and purple. Tahitian pearls range in size from 8 mm to 16 mm.

The other birthstones for the month of June are moonstone and alexandrite.

Credit: Photo courtesy of Adam Neeley.