Pearls, no matter whether they are natural, cultured, or imitations pique the curiosity of almost everyone interested in jewelry. (when I taught gemology, the pearl class was always the most popular.) Most are fascinated when they hear the details of how they form and the differences among the various varieties of cultured pearls. They are also confused by the huge price variations between pearl strands or jewelry pieces that may look quite similar. I guess the best place to start is to give you a brief overview of how natural pearls and cultured pearls are created and how they differ.
Pearls, whether cultured or natural, form due to the same circumstance.
Nacre is the liquid substance that is secreted from the mantle tissue that coats the rough interior surface of the shell where the oyster lives. The nacre hardens to form a beautiful iridescent surface called Mother-of-Pearl.
If an irritant, usually a parasite, finds its way through or into the shell and settles into the body of the oyster or mussel it will protect itself by forming a sac around the foreign matter. To protect itself, it will coat it with layer upon layer of the same organic liquid that hardens to form the pearl’s smooth, hard surface.
The difference between natural and cultured pearls is the circumstance that triggers their formation. A cultured pearl is man’s partnership with nature and is formed when technicians surgically implant the irritant rather than the process occurring naturally. Technicians on pearl culturing farms implant mother-of-pearl bead nuclei within the bodies of oysters along with a piece of mantle tissue that grows around the bead. This tissue secretes nacre and the mollusks are returned to the water to allow the cultured pearls to grow. BTW, if you have a steady hand, this job may interest you as these technicians are paid more than a million dollars a year!
What Kind Of Pearls Do I Have?
You might assume that the strand that was passed down to you from your mother or grandmother has a great deal of intrinsic value. That is not always the case. With all the different varieties of cultured pearls and imitations out there, it is hard to know what exactly you are looking at. But what is important is the sentimental value of jewelry that has been passed down; you cannot put a dollar value on family heirlooms.
As described above, natural pearls are created spontaneously, without man’s help or intervention. Cultured pearls are produced on pearl farms, where man induces the process, controls the environment, and baby-sits the oysters until they form cultured pearls, anywhere from six months for Akoya to three years for South Sea cultured pearls.
For natural pearls to reach substantial sizes takes years and years. Natural pearls will be 100% nacre; the only way to determine if pearls are natural is by X-ray or by slicing them in half. There are few natural pearl strands left today, and most are found in museums. The misconception is that natural pearls will be perfect, which is really not the case, but regardless they are extremely expensive due to their rarity.
Prior to the mastery of the culturing process in the early 1900s (by the King of pearls Mikimoto), the only way to obtain pearls was for people (mostly women) to dive to the bottom of the ocean floor and collect oysters in the wild, in the hopes of finding pearls once they opened the shells! Due to the high demand for pearls, the oyster beds were eventually depleted. The number of willing divers also dwindled due to lung diseases that severely shortened their lives. Luckily Mr. Mikimoto’s successful new process brought beautiful cultured pearls into the marketplace and filled the demand. Cultured pearls only become popular in the U.S. after WWII, when servicemen returning from Japan brought gifts of cultured pearl strands back to present to their wives.
Cultured Pearl Varieties
Here is a list of the varieties of cultured pearls and the major sources. If you have pearls and are unsure of the variety, take a look at the information below, it might help you identify your strand or piece of jewelry that features pearls.
- Freshwater – China, U.S. (limited): are produced with or without bead nuclei. Abundant, pastel colors, accessible and affordable, are the keywords to describe freshwater cultured pearls- They are the mainstay of contemporary pearl jewelry design. Sizes: 6mm-12mm.
- Akoya (name of the oyster) Japan, China: Prized for their high luster, the finest have mirror-like reflections, white or rosé, with rosé overtones. Sizes: 2mm-10mm (9mm-10mm extremely rare)
- South Sea
– Australia, Indonesia, Philippines: Cultured South Sea pearls are the largest and rarest variety of pearls and are known for their satiny or silky luster. The finest have very high luster. White, silver, or golden. Sizes:10mm-20mm
Tahitian – Black South Pacific French Polynesia (Tahiti
and surrounding islands) Metallic luster – Although many think of Tahitian pearls as having a black body color, they form in a variety of colors in dark shades of gray, green, brown, and blue, with green and/or purple overtones. Sizes: 8mm-18mm
- Keshi – Baroque (interesting and unique shapes) pearls that can form as a by-product of the culturing process, the most valuable come from South Sea and Tahitian oysters and most often have high luster. Sizes 2mm-10mm
- Mabé – Formed by attaching a plastic form (half-sphere) inside the shell of South Sea oysters along with mantle tissue that covers the form with nacre. After one year the form is cut away and backed with a piece of mother-of-pearl. Most often used to make earrings. They are also known as assembled pearls.
- Seed Pearls – 2 millimeters or smaller – no bead nucleus, these are natural, but a by-product of the culturing process
Mother-of-Pearl – The nacre coating that lines the inner shell of oysters. Used in jewelry, to make buttons, guitar frets and ornamental objects.
Cultured Pearls Value Factors
All cultured pearls are assessed for the following factors:
- Size: Cultured pearls range in size from approximately 2mm – 20mm. Larger sizes are the rarest, as are small sizes in some varieties.
- Color & Overtones: The body color (first color we see) Overtones, the sheer color(s) that lie over the body color. Example: White with rosé (pink) overtones or dark gray with purple or green overtones, etc.
- Luster: surface shine and reflections – Cultured pearls can have dull to very high luster.
- Shape: round, near round, symmetrical, baroque – round pearls are the rarest, thus the most expensive shape within each variety – example: a round South Sea
cultured pearl is more expensive than a near round, etc.
- Surface Complexion: bumps, cracks, pits in the nacre coating – Blemish-free cultured pearls are the rarest – As they are an organic material blemishes are very common. Luster is the most important. It has been said that a flawless pearl is as rare as a flawless diamond.
- Nacre Quality/Thickness: Can only be measured by x-ray or by cutting the pearl in half – The bead nucleus should not be not visible through a good nacre coating.
- Matching: In strands, or any piece with multiple pearls, the factors above are matched as closely as possible to create a piece with visual harmony.
Keep in mind that cultured pearls are organic (formed from a living organism) so as you look at strands, no two pearls will be exactly alike – there will be slight variations in color, size, and luster. The goal is to match pearls to create strands with visual harmony.
An imitation is something that just looks like something else. I remember when I was very young, we had pearl necklaces made of plastic where the beads snapped together and we could make them any length we wanted. Oh how grownup and glamorous we felt.
More sophisticated imitations, like glass beads covered in pearlescent solutions that imitate nacre coatings have been around for more than 100 years. They are covered with clear lacquer or other coatings to protect the surface. The tip-off for these imitations is that the beads, “pearls” are heavier and over time the lacquer coatings tend to turn yellow and or chip off. The highest quality imitation pearls are produced by a company named Majorica®, located in Majorca Spain, They have been producing imitation pearls since 1890. These imitation pearls will last a lifetime if properly cared for. Click Here to learn more about Majorica® imitation pearls.
Caring for Cultured Pearls
- Do not wear pearl strands with any other jewelry that will scratch the delicate nacre coating.
- Do not expose to hairspray, fragrance, or body lotion
- Do not store in safety deposit boxes for long periods of time (years) the nacre coating will dry out and crack
- Do not clean in commercial jewelry cleaners. They contain harsh chemicals that will destroy the nacre
- Remove pearl jewelry prior to playing sports or to clean house
- Pearls should be the last thing you put on and the first thing you take off
- Always store in the original packaging or soft lined pouch
- Professionally cleaning and restringing is recommended once a year if you wear your strands often
- When caring for pearls at home, wipe with a soft, slightly damp cloth
If your question was “What is the difference between cultured pearls and real pearls?” I hope you found this article enlightening! There is nothing that is more feminine than pearls and they should be a staple in every woman’s jewelry wardrobe.
Please leave a comment or question below, as I would love to continue the conversation!
Thank you for reading my article!
Francesca de Granville, G.G, F.G.A.