One of the most beloved of all gems is the pearl. It’s luminous glow, lustrous surface and connection to both the ocean and the moon has captivated jewelry enthusiasts for centuries. Perennially popular, pearls are always perfect for brides and they also exemplify the current “quiet luxury” trend. At one time, pearls were among the rarest of all gems. When a pearl was found it was a happy occasion and often cause for celebration. So what is a natural pearl and what is a cultured pearl and more importantly, what’s the difference?
Forming a Pearl
A pearl — either natural or cultured — forms when organic material finds its way into a mollusk. The organic matter is irritating to the mollusk, which responds by producing nacre to relieve the irritation. As layers of nacre collect, a pearl is formed. Nacre is a combination of the mineral argonite, which is calcium carbonate and conchiolion, a protein secreted by mollusks. A natural pearl forms when the organic matter finds its way into the mollusk by accident and a cultured pearl is formed when a human places the irritant in the mollusk.
Natural Pearls
Back in the days of the ancient Egyptians and Romans pearls were considered to be the most valuable gem. According to a story by Pliny the Elder, a Roman author and naturalist, Cleopatra bet Roman general Marc Antony that she could host the most expensive dinner party ever. When the two sat down to dinner a cup of wine (or possibly vinegar) was placed on the table with one of two large natural pearl earrings that Cleopatra always wore. Cleopatra crushed the pearl, dropped it in the liquid and once it had dissolved, drank it. Needless to say, she won the bet. Pliny the Elder, considered to be one of the world’s first gemologists, noted that the pearls were highly valuable – worth what would be millions in modern dollars.
Pearls, prior to the development of cultured pearls, were so rare and expensive that they were reserved for royals. And it was treacherous to find these ocean treasures, pearl divers would go deep into the ocean searching for pearls, but often returned to the boat empty handed as there was no guarantee that a mollusk would have a pearl.
Enter Mikimoto
The pearl market changed in the 1920s thanks to a name we all know, Kokichi Mikimoto, a Japanese vegetable farmer turned pearl farmer. He is widely credited with developing cultured pearls, which are formed when a human places an irritant in a mollusk prompting it to create nacre that forms a pearl, rather than waiting for an act of nature as happens when natural pearls are formed. After many years of trial and error, Mikimoto was able to successfully culture pearls and in 1908 he patented his process.
By 1921, cultured pearls were on the market. It’s one of the reasons that fashionable women of the Art Deco period were able to adorn themselves with long ropes of pearls, the gems were now readily available at an accessible price point.
Like any new technology, cultured pearls had their critics. A London-based newspaper wrote an article claiming that cultured pearls were not “real”. The article triggered a dispute over the validity of cultured pearls that resulted in a lawsuit brought by Mikimoto that drew international attention to these gems. Mikimoto won the lawsuit and pearls were on their way to reaching a new popularity never experienced before due to the lack of availability and stratospheric prices of natural pearls.
How are Cultured Pearls Raised?
Today, it is very rare to find a natural pearl unless it is in a piece of antique jewlery; cultured pearls rule the market. So how exactly are pearls cultured? On pearl farms — in oceans, rivers and lakes — baby mollusks are raised in large nets until they are mature enough to be nucleated, which takes about two years. Skilled technicians then gently and carefully implant a nuclei into the mollusk. From there the mollusk is placed back in the water where they are carefully tended to for about six months to two years. The longer the pearl stays in the mollusk, the larger it will be.
How do you know if a pearl is natural or cultured? Generally, a piece of jewelry made prior to 1900 will have natural pearls. Cultured pearls were sometimes found in jewelry during the first twenty years of the 20th century, but natural pearls were also used. The only way to verify if a pearl is natural or cultured is to have it examined with the proper gemological equipment. If you’re considering purchasing a natural pearl, ask for a lab report from a reputable gemological laboratory for assurance that the pearl is what it is represented to be.
Featured image (top of page): Victorian 15-karat gold bangle with a lattice of diamonds and natural pearls, English, inscribed “wedding present to Margaret Leicester Warren from the Galley Genantry, 1875”.
First: Platinum topped gold, old mine cut diamonds and natural saltwater pearl earrings, circa 1880; Second: Edwardian natural pearl, diamond, silver and 18-karat gold brooch; Third: Kokichi Mikimoto inserting a nucleus in a pearl shell, 1945 -1954, photo public domain; Fourth: Cultured pearl, aquamarine, diamond and 18-karat white gold earrings, signed Seaman Schepps, circa 1970s.
Authored by Amber Michelle