Types of Pearls Used for Jewelry

Types of Pearls Used for Jewelry 

Natural Black PearlThere is something quite magical about the lustrous beauty of a pearl ring or the iridescent quality of a row of pearls on a necklace.

  However, not all pearls are the same.  Before choosing your perfect piece of jewelry, here is some information about the different types of pearls that you will find.

What is a natural pearl

Natural Pearl 2In its natural state, a pearl is formed inside a mollusc shell when its tissue is damaged by a parasite or some other event. 

The response is for the mollusc to secrete a substance called nacre into the pearl sac that then forms a cyst during the healing process.  Nacre is produced from the mineral calcium carbonate and a fibrous protein called conchiolin. 

As the nacre continues to grow, it builds up in layers and fills the pearl sac until it eventually forms into a pearl. It is the nacre that gives the pearl its luminous, iridescent quality that makes it one of the most popular and sought after gems for jewelry.  

These days, natural pearls are quite rare and expensive so cultured and imitation pearls are the ones generally found.

Cultured Pearls

Most types of pearls used for making pearl jewelry are “cultured” pearls.  These are created by surgically implanting a foreign object or seed nucleus into the tissue of an oyster or mollusc to start the process of pearl development.  This method mimics the development of a natural pearl so well that the end results for a cultured pearl and a natural one can look very much the same.

A large cultured pearl can take up to 6 years to develop although most pearl farmers harvest them between 2-3 years after the seeding implantation.

Around the end of the 19th Century pearls could only be found growing naturally in the sea.  Japanese pearl divers had to search for oysters on the ocean floor and check each one to see if it contained a pearl.  Pearls were therefore a lot more difficult to obtain and as a result very expensive.

The discovery that pearls could be cultured led to farms being set up for pearl production around the early 20th century .  This resulted in a huge increase in the amount of available pearls that could be used for producing jewelry and sold at a much cheaper cost.

There are two main categories of cultured pearls used in the manufacture of pearl jewelry:

  • Freshwater pearls – dominated now by the intensive farming methods of China
  • Seawater cultured pearls such as the Akoya, South Sea and the dark lustrous Tahiti pearls.  

Freshwater Pearls

These pearls are created using freshwater mussels and differ from Salt water pearls in their type of luster, which is softer and with a glow that comes from deep within the pearl.  The reason for this is that freshwater pearls are comprised of much thicker nacre than that of saltwater pearls that have a more brilliant superficial luster due to their thinner layer of nacre.  The growth process of a freshwater pearl is similar to that of a natural pearl which makes it a much more durable gem for jewelry worn on a regular basis.

Improved Chinese techniques for creating freshwater pearls have led to high quality gems being comparable with the Akoya saltwater pearls – and in some cases exceeding them.  The tissue nucleation process now used in China has enabled up to 40 pearls to be grown within one Freshwater Pearl Mollusc.

When compared with the Japanese Akoya and South Sea Pearls, that generally only produce one pearl per oyster, the Freshwater Pearl industry in China has now become the largest producer of cultured pearls in the world.

With the ability to produce more pearls per mollusc together with a greater success rate in growing rounder pearls, the Freshwater Pearls of China now sell for a fraction of the cost of comparable Akoya pearls.  The lower commercial price of pearls has meant that the public can now buy affordable rings, necklaces and other pearl jewelry more easily and at a lower cost than ever before.  

The benefits of freshwater pearls is that as well being that little bit more durable they are now available in a wide range of colors.  These include pretty pastels like pink, peach and lavender through to the deeper colors of plum, purple, chocolate and black pearl.

Akoya Pearls

The term Akoya is used internationally to signify Japanese saltwater pearls, although they are also cultivated in China as well as along the coast of Japan.

Akoya pearls are produced from a small pearl oyster, the Pinctada fucata martensii, with up to 3 bead implants being inserted into one mollusc to create the cultured pearls.

Saltwater pearls take around 6-18 months to develop.  A slow growing period will create a much smoother and more even layer of nacre and therefore the pearl is likely to look more rounded and lustrous – the perfect shape for a beautiful pearl ring or an iridescent pearl necklace that will bring a glow to your skin.

South Sea Pearls

These pearls are produced by the large pinctada maxima mollusc, and found in the Indian and Pacific Oceans.   The warm water and healthy environment of the South Seas combined with the two year period it takes for the pearl to grow within the mollusc, creates some of the largest pearls to be found.  An average size South Sea pearl grows to between 9 – 20 mm.

South Sea Pearls possess a satin like quality that it unlike any other pearl.  Their colors range from white through to silver with some rarer pearls exhibiting a golden hue.

Tahitian Pearls

Although Tahiti is the commercial center for Tahitian pearls, there are no pearl farms on the island.  The pearls are grown in a variety of farms throughout the French Polynesian islands and further afield.  The pearl growing oyster is 12” in size and produces larger than average pearls in natural dark colors such as: black, charcoal, silver and green.   

Mother of Pearl

This beautiful iridescent material originates from the nacre found inside a mollusc and is the same substance from which the pearl is made.   The nacre is crushed into a powder, then moulded and heated into the desired shape by a process known as sintering.

Mother of pearl has been used for centuries to embellish furniture, ornaments and  jewelry.  It is a popular material for rings, earrings and necklaces due to its beautiful iridescent appearance.   Because mother of pearl is made from nacre, the surface can be susceptible to scratches.  Care should therefore be taken when wearing this jewelry on a regular basis as well as when it requires cleaning.

Imitation Pearls

Designed to replicate natural or cultured pearls, imitation ones are commonly created from materials such as glass, plastic or part of a mollusc shell.  The iridescent appearance is created using one of many different techniques and substances.  These include glass beads coated with pearlescent materials and hollow beads filled with wax.

For more information about choosing and caring for your pearl ring and other jewelry, see our article: Choosing a Pearl Engagement Ring and How to Care for Pearls.

To see our Pearl Ring Selection – our hand-picked selection of pearl rings from our favorite jewelers. CLICK HERE.








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