How Pearls Get their Color

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So, you want to know how pearls get their color. Let’s go ahead and throw out any ideas of dyed or treated pearls. I have written about dyed pearls before but I want to tell you about how natural pearls get their color. And, when you think about it, it makes perfect sense.

how pearls get their color - example of two tahitian pearls - the pearl girls

Let’s review what a pearl is. So, there is a mollusk living a glorious life in the river or ocean. This fairly sedentary mollusk becomes a natural habitat for other organisms. In a river, maybe it is just a little moss or organic matter. In the ocean, the mollusk might be covered in barnacles or it might get a little aquatic visitor. But, usually, these mollusks are living in an ecosystem and, occasionally, these mollusks are invaded by other species. I wish I could say it is something sweet like a little piece of sand or something. More likely it is a bacteria or sea squirt or something like that. This organism or inorganic matter damages the soft inner body of the mollusk and, to heal and protect itself it creates a pearl sac and starts making a pearl. How? It uses the epithelial cells which secrete a hardening liquid. This liquid is usually secreted to make the mollusk shell. This same material is not used to coat the invader and to produce a pearl.

So, quite simply, a mollusk is using the same material it uses to make its shell to make its pearl. So, the color of the pearl will be the same color as the shell. The black lipped oyster is such a great example.

tahitian black pearl in a shell - one tahitian pearl

Do you see how the edge of the shell is black? And then there is some silver coloring, some brown and a silvery white color? A black lipped oyster can produce a black pearl (with all its variety of shading!), a grey colored pearl, a brown pearl or a white pearl.

When you ask how pearls get their color, know it is all in the shell!


Read more on Chocolate pearls here…

*** but also know, dye goes a long way to imitate the natural color of pearls! Any reputable pearl seller will tell you whether the pearls have been dyed or not! ***

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2 Replies to “How Pearls Get their Color”

  1. I’ve noticed on Facebook recently people opening oyster shells and taking out crazy coloured pearls, like bright blue, silver and dark pink. I assumed they were natural, as they are still in the unopened shells, but after reading a few of your articles I’m understand these colours aren’t natural. Do you know if these pearls are likely dyed? Perhaps the water the oysters are kept in is dyed? Any thoughts on this wouldn be appreciated. Thanks.

    1. Hi Kate!

      Thanks so much for reaching out! There is a definite craze going on of people opening oysters to get pearls. And it definitely seems like lots of fun! That is what I get to do on my trips to pearl farms and it is so exciting!

      Unfortunately, what these pearl folks are not telling you (and might not know) is that this is an orchestrated event. There are factories hard at work in China taking oysters, opening them up and putting the pearls in them for people then open and “discover.” You see, these pearls are not naturally in these oysters. They have been planted there.

      These pearls have come from a pearl harvest, they may have gone through post production treatments. The colorful ones have sat in dye for weeks to get their color. The white pearls might have been treated, bleached or polished. Then the pearls are implanted into much younger oysters. So, these are not a true – oyster out of the water – find.

      Here are the ways you know this is true…. first, most of the oysters they are opening are too young and too fragile to grow a pearl. Oysters have to be at least two years old to start the pearl making process. Most of them grow to three and a half years old by the time the pearl is harvested. Notice how easily their shell cracks? They are very young oysters.

      Next, the pearls are not in the gonad of the oyster. That is where saltwater pearls are nucleated so the person opening the oyster would have to open the gonad to get the pearl. So, the placement of the pearl is a giveaway.

      The wild colors are not natural. An oyster or mollusk can only produce a pearl the same color as its shell. Why? Because that is the same material it uses to make a pearl. So, if the oysters shell is dull gray and the pearl is bright blue… something is fishy! This blue pearl was not formed within this oysters… and no, they do not put dye in the water while the pearl is in the oyster.

      Finally think of output… on average, half of all nucleated oysters do not produce pearls. Are half of the oysters opened without pearls? I doubt it since that would ruin the excitement. Frankly, opening oysters at a true harvest can be kind of depressing. Yields can get as low as 30%. And, do some of the harvested pearls look awful and need to be thrown away? Let’s say they x-rayed all the oysters and knew that every oyster had a pearl inside. Well, they will not all be gem quality pearls. Some of the pearls will be downright awful looking! So, if all the oysters have pearls and all the pearls look great, then the “pearl opening party” has been all part of a set up.

      I went to go see one of these factories when I was in China and at the last minute was barred from going in. Otherwise I would have some videos to show about the “set-up”.

      Again, I know these are fun experiences and a neat thing to do. And I do think they are actually selling real pearls instead of fake ones, which is a plus! But, they may not be entirely forthcoming about the true origin of their pearls.

      I hope this helps clear things up for you!



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