Natural Pearl Tests
Use some of the following natural pearl tests to determine if you have a natural pearl.
How to tell a natural pearl from a cultured pearl.
As the market becomes more and more flooded with the large variety of cultured pearls,
natural pearls will only increase in desirability and value.
But....how can one tell for sure if a pearl is natural?
It is becoming increasing more difficult to distinguish the differences, especially, since, in the early 1960's the tissue nucleated pearl showed up in the markets, which means that a cultured pearl can now also be totally nacre like a natural pearl. Before this, a bead nucleus was the sign of a cultured pearl.
Even the Gemological Institute of America (GIA) which took over the pearl testing equipment of the Gem Trade Lab (GTL) in 1949 and has applied natural pearl tests to thousands of pearls attest to the challenge of determining natural pearls.
It takes years even for experts to spot natural pearls with their human eye and touch...but apparently this art intuitive natural pearl tests can be developed over time.
Leonard Rosenthal, once known as the "Roi do la Perle" or the "Pearl King," who at one time was the world's largest dealer of natural pearls, could identify natural pearls by only looking at them.
If purchasing a pearl which the seller claims to be natural, insist on documentation of natural pearl tests from a reliable gemology lab.
Natural pearls do exist and can be found in many places. You may even see ads on this page for natural pearls.
I have personally talked with people who have found natural pearls, own several of them and consider them as personal treasures. Here you can see several natural pearls that folks have found often by accident.
Here are some natural pearl tests which can help you to discover whether or not a pearl is natural.
1. View with a "black light," or ultraviolet lamp.
This is especially useful if the pearl hasn't been drilled. Under a black light cultured pearls usually have a milky, bluish-white look to them, plus there will be a uniformity in color of cultured pearls in a necklace. Natural pearls in a strand will have variations in color intensity from pearl to pearl and will usually appear tan or yellowish under a black light.
2. View with a fiber optic light or high powered penlight.
Investigate the pearl from different angles and slowly over its surface. Sometimes it's possible to see the outer dark parallel edges of the mother-of-pearl nucleus this way, especially in pearls with very thin nacre. Seeing orangey-colored irregularly shaped spots also indicates cultured pearls.
3. View the drill hole.
With a jeweler's magnifying lens, called a loupe, carefully examine the drill holes. The line between the mother-of-pearl nucleus and nacre may be visible as a darker line. Sometimes bleach has removed this darker line and also when the nacre is thick the brownish layer is harder to see.
If the drill hole is tiny...it can sometimes indicate a natural pearl, since they are sold by weight...so the smaller the hole, the more the weight.
4. View with an x-ray.
Often, this is the best way to prove pearls are natural. X-rays alone, aren't enough, but professionals from a gemology lab should be the ones to do the interpretation of the x-ray.
5. Research the history of the pearl.
Sometimes this would be impossible in cases especially of very old pearls or those found at an auction, for example, but in cases of recent finds, one could verify its discoverer and its authenticity as a natural pearl.
After reading these natural pearl tests, you may like to know other pearl tests.
Special thanks to Antoinette L. Matlins, PG and her book, "The Pearl Book--A Definitive Buying Guide, for most of these test ideas.