Why The 'Tooth or Grit Test' For Pearls is False

The often asked "are my pearls 'real or 'fake'?" is one of the top jewelry questions if not the #1 asked in jewelry forums and pages all over the internet. It is followed up by the #1 response of do the 'tooth test' which is also known as the 'grit test' or 'friction test'. If your not familiar with what that is, then you either don't have pearls or never asked the question of what kind of pearls you have. First before going any further there is a translation between what the public uses for pearl terms and what the jewelry trade uses. To eliminate confusion, the public and sites that want to use terms that the general public will understand use the descriptive terms of 'real' and 'fake' for pearls. The jewelry industry goes by 'cultured' or the rarer 'natural' pearls in place of 'real' and 'simulated' or 'imitation' in place of 'fake'. For making this easier to follow I will continue using the general public's use of the terms 'real' and 'fake'. 

The test is where you either rub two pearls together is refered to 'the grit test' or rub a pearl on the sharp edge of your tooth is refered to as 'the tooth test'. The theory of this test is if you feel a resistance when you rub two pearls together or feel a gritty resistance against your tooth, they are 'real' pearls. If the beads glide smoothly against one other or slide over your tooth edge with no gritty resistance, they are 'fake' pearls.

Where this test is best applied is when it is done as a secondary test in combination with high magnification and not relied on solely as the only source of identification. The reason this is the most unreliable test to use on both types of pearls is that 'fake' and 'real' pearls can have coatings and treatments that make the surface test completely the opposite of what they are. Most that are familiar with the test have heard that there can be gritty coatings on 'fake' pearls that mimic the grit and resistance giving a false positive test result of 'real' pearls. What is never mentioned and not even widely known unless you deal in the cultured pearl market is that for the past 20 to 30 years pearl harvesters have applied treatments to improve surface imperfections and give a higher luster that make lower quality 'real' pearls have a smooth glassy surface by covering over the gritty nacre layer and polishing the surface. Doing this artificially improves a cultured pearls surface imperfections and gives the impression of higher luster and a better quality pearl than it actually is. Another popular treatment is lacquering the surface of a 'real' pearl of lower luster to make it look like it has a higher luster. However the layer is not permanent and can show peeling on the fine layers over a short period of time. These coating enhancements, both the polished wax layer and the lacquered layer makes the pearl's surface slippery with no resistance that covers over the gritty texture of nacre and will give a false result on a 'real' pearls being misidentified as 'fake pearls.

For best identification practices in obtaining the most accurate results, always do a couple different tests before making the judgment call. Study on learning how to identify pearls from magnification (the higher the better, 50x is recommended) as the first main test being the most important deciding factor...even then, if your not regularly dealing in pearls take them to someone who does for an experienced 2nd opinion, as pearls are among the most difficult items to properly identify even by the professionals. The difference in a wrong ID can be thousands of dollars your loss if you misidentify strand of Akoya cultured pearls as 'fake' because they feel smooth by the tooth test.

Fortunately there will always obvious imitations that you don't even need to test because they are evident by sight examination alone. Luster treatments though are much harder to spot. If the strand is not obvious as 'fake' pearls your go to method to test should be high magnification of the recommended 50x over the resistance/glide test...... as that can go very wrong if it's all your relying on. Now happy hunting on finding all those misidentified 'real' pearls that were tagged as 'fake' because everyone is going by what should be called the unreliable 'infamous tooth test'!

An educational link that describe the waxy, polishing and lacquering treatment processes :

https://www.pearl-guide.com/th...

How to properly test your pearls :

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