All About Pearls: Size and Shape

custom collection, Yael DesignsGolden South Sea cultured pearl, yellow and white diamond pendant, Custom Collection, Yael Designs

Just like diamonds, pearls have set standards by which they are judged. These factors are: size, shape, color, luster, surface quality, nacre and matching.

Leone Collection, Yael DesignsSeed Pearl, black and white diamond tassel necklace, Leone Collection, Yael Designs

Size is a relatively straightforward consideration. There are two main types of cultured saltwater pearls: Akoya, and South Sea and Tahitian. Because of Mikimoto’s influence, cultured Akoya pearls are the most commonly known. These were the type of oysters the pearls of which Mikimoto worked with and marketed. Cultured pearls from these oysters typically range in size from 2mm to 10mm. South Sea and Tahitian cultured pearls are grown in a species of oyster that is larger than Akoya. These oysters; therefore, are capable of growing larger cultured pearls, ranging in size from 8mm to 18mm. Interestingly, cultured pearls are sold by pearl farmers to dealers by carat weight, but sold to their final owners using millimeter measurements.

The size of Akoya pearls should not be judged against the size of South Sea and Tahitian pearls because their size ranges and therefore their rarity at different sizes are not the same. All other things being equal, a 10mm Akoya cultured pearl is worth more than a 10mm South Sea cultured pearl because the Akoya is rarer than the South Sea at that size.


Orb Pearl Collection, Yael DesignsOval-shape golden South Sea cultured pearl and diamond earrings, Orb Pearl Collection, Yael Designs

As mentioned in our previous blog, round is a rare shape for natural pearls. The process of culturing pearls has made round pearls “The” shape. This is because salt water oysters can be nucleated with round beads, making it more likely that the finished product will be round. But because these are naturally formed gems, even with the round bead, their shapes still vary. Round is the most popular shape, followed by drop or teardrop. There are many other shapes besides, such as near-round, oval, button, baroque (which refers to an irregular shape) and semi-baroque. There are additional names for fancy shapes, but these cover the basics.


Baroque Freshwater Cultured Pearl and Diamond Pendant, Yael DesignsBaroque freshwater cultured pearl and diamond pendant, Yael Designs

Freshwater mussels are traditionally unable to be nucleated with beads as they have a high rejection and death rate, so traditionally have been nucleated with only a piece of mantle tissue from a donor mussel. However, freshwater cultured pearl farmers have been experimenting with crossbreeding mussels so that they can accept round beads as well. One reason for this is that cultured pearls nucleated with beads are often heavier than those grown without; and because pearl farmers sell by weight and not size, this factor alone increases their cultured pearls' prices. However, this has led to amazing innovation in the field. One of the most exciting new freshwater cultured pearls types to come out in recent years is called the Edison Pearl, and the farmers of these cultured pearls have managed to achieved a nearly perfectly round shape consistently. But there are also wildly popular shapes such as the fireball, which is a round shape with a wing of nacre trailing behind like a comet; and the Kasumiga or ripple cultured pearls which have a textured, rippled surface. Non-round freshwater cultured pearls have many names dependant on what they look like including: rice krispy, potato, cross, biwa, coin and bar.


Baroque Freshwater Cultured Pearl and Diamond Pendant, Yael DesignsBaroque Freshwater cultured pearl and diamond pendant, Yael Designs

What you have to look forward to in our next blog: nacre and color.



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