And here we are back in the saddle and readying to continue with the Ultraviolet light test series. Since there are many varieties of pearls to compare I have chosen to separate them into groups based mainly on their COLOR. And why do it this way? because it just seems so simple and obvious, and although many people will say there is not much in common between an Australian South Seas Pearl (SSP for short) and a Chinese Freshwater pearl (CFWP, also for short) –I mean, the differences are jarring: SSP are produced in the sea with a Pinctada maxima pearl oyster, and most CFWP are grown in rivers/lakes/ponds with Unionidae pearly mussels- they have a very similar color and overall look.
Still, each group will have its own sub-group for analysis and comparisons, so as not to cause much discomfort among those that prefer to keep their apples apart from their oranges. So, shall we jump into the tests?
White Pearl Group: Akoya, SSP and CFWP
In this group I decided to include the most common pearls in the World, just with CFWP and the saltwater Akoya pearls you can say you’re reaching well over 95% of the World’s production of cultured pearls. White South Sea Pearls (SSP), which include Australian and Indonesian productions, are far less abundant and larger-sized than its counterparts, but their color is very similar in a silvery white variation. Let us place these pearls next to each other and compare their look:
The similarities in the overall look of the pearls is more than evident, but on close inspection there are subtleties that are revealed: pearls are not like other gemstones and we should not expect sharp, dramatic differences but their beauty is more in the realm of “the little things”. Some can be revealed by close inspection with a loupe/triplet, using a special background and light situation or by immersing them in water (The Water Test). On the photo above you may notice that the pearl on the left (an Akoya Pearl, sometimes called “Mikimoto” or “Japanese” Pearl) has some interesting “stripes” (faint ones, these are the stripes you can see in the mother-of-pearl nucleus; you can see these due to this pearl’s thin nacre coating), that the middle pearl (a Chinese freshwater pearl) has a yellowish-pink tint and the one on the right (an Australian South Sea Pearl) has a greenish tint to it. Some of these features are due to the LED lamp I used to shoot the photos, but they are not as evident in a normal light situation. Anyway, I employed the same light (and distance from it to the pearls) for all this study, so all pearls are subject to the same treatment.
So, how will these pearls react to long-wave UV light exposure? Let us see and compare.
As you can see, the Akoya and Freshwater pearls (left & middle) have a remarkably similar glow (pure white-blue) and the South Seas one (right) has a greenish-blue cast to it. One thing we have to keep in mind for he rest of this series is that every UV lamp, background setting (I recommend a black cloth) and ambience light (a darkened room is best), you employ can affect the results so you may see something different from these results. Finally, these are photos and our eyes are better at capturing the glow/fluorescence effect.
I used 3 different Akoya pearls now to see additional results on this group. I had a very white Akoya, a cream-beige (“golden”) Akoya and a “black Akoya” (irradiated) pearls for this group. Results were quite interesting.
On the image above you will be able to see several things, but first I want to point out the most evident one: a small Chinese Freshwater pearl (CFWP) which I call “the blank pearl” (the “PC” is to be used for Spanish as “Perla China”) and this is something I will do an all UV photos that do not include a CFWP. What for??? It will serve us to compare the standard blue-glow of the “standard pearl” with others. That is the reason you’ll see it there.
Anyway, the white Akoya has the expected color but now we see 2 interesting things: the golden Akoya has a very faint glow –almost none- and it is of an golden-orange color, whereas the “black Akoya” has no glow at all. For the most part fake/imitation pearls display no fluorescence (but I have seen some that do). What does this mean to us? That dyed pearls will not glow the way a pearl does, and that the golden-yellow pigments somehow interfere with fluorescence as well. Interesting isn’t it???
In this instance I have some traditional freshwater pearls for inspection. I skipped the normal shot because they are simply unremarkable…just plain white pearls. Their glow is the one we quite expected: the beautiful blue glow.
Conclusion & Closing Remarks
White pearls glow with a beautiful blue-green glow under long-wave Ultra-Violet light, but some pearls of the “white pearl” group may not display this fluorescence, this would include some (I can’t say that all until I can check thousands of pearls) of the golden and dyed/irradiated pearls.
What have I missed? I do not have any “Blue” nor “Pink” Akoya pearls for testing, and there are many cheaply dyed freshwaters pearls that I should include in these tests too. I will, as soon as I have samples. If you care to share your personal research or to send me samples I will be more than happy to update this entry to include your personal findings. Please feel free to write to us by means of the “Comments” section.
Stay tuned for the next group: Black Pearls.