shell based pearl v cultured pearl


Aug 21, 2017
Hello I am new to this forum, and have just discovered my new found love for pearls. I never thought i would love pearls so much, but the more i read and the more i play with them, the more i LOVE them.
anyway, a gemologist friend of mine, taught me how to candle pearls with just my iphone. so off i go to candle small but growing pearl collection.
I have a pair of golden akoya pearls, and when i candled them, i could see that there are lines opposed to having a faint nucleus and a glowy nacre.....then on the weekend, i saw a pair of pearl earrings priced very cheaply and so i proceeded to candle them, only to find on the tag it says shell based pearl. lo and behold, it also has now i am worried that my supposed akoya pearl studs are immitation.

so how does one tell the difference between genuine pearls as well as man made ones.....i saw one of the members posts showing candling of pearls...and mine did not look like that.....

Thank you in advance.

Hi gracecjy,

Good questions!
The lines you saw in your akoya pearls are the layers in the bead nucleus, which is made of mother-of-pearl (shell). The bead is implanted in the oyster's gonad along with a bit of mantle tissue from a donor oyster, which results in a pearl sac forming around the bead. The sac secretes nacre that covers the bead. This is how a cultured akoya pearl is formed.

The "shell based pearl" you referred to may also have a shell bead inside, but the coating is man-made. It may be made of ground-up nacre from the inside of a shell, or it may be made from ground-up fish scales, in a kind of shellac. Either way, it's an imitation pearl, because the nacre was not laid down over the bead by the oyster. The bead was dipped in the liquid coating material in a factory.

One quick test for imitation pearls is to rub 2 of the pearls together gently. Fake pearls will glide easily against each other, while real pearl nacre is a little bit gritty or resistant. This is called the Tooth Test as you can also rub the pearl against the edge of your front tooth instead to feel the grittiness.
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Some good quality fake pearls also have a slight gritty feel to them when they are rubbed, so it isn't a 100% sure way of telling if they are fakes or not. You can also check the drill holes. Fake pearls often have sloppy holes and you'll see some accumulation of the outer layer sometimes, and other times, you might see some peeling of the outer layer. You can also tell by looking at the entire strand. If all the colors are identical, and the shapes are the same, then you've either got a superior strand or a fake. You should see some uneven nacre or tiny pit marks, even in the best of strands.

Here's an example of some vintage blue akoyas a friend had that were in poor shape. The nacre on some pearls was so thin you could see the bead inside. Not all the beads have swirls, as you can see. This picture was taken outside in full sun, but under a deck.

Just for fun, this is what the same pearls look like in ideal lighting.
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Even my Majorica imitation pearls, which are excellent fakes, feel smooth when rubbed. I have yet to find a fake strand that doesn't feel smooth, but then I don't own any "shell pearls" so maybe they can feel gritty, idk.