A natural pearl displays fluoresce under ultraviolet light because of the presence of natural organic compounds in its nacre. Akoya cultured pearls form in the Pinctada Fucata oyster. These oysters are thriving in the hidden bays off the coast of Japan in the cold saltwater of the Pacific Ocean.
Untreated white to cream-colored pearls generally show blue to greenish blue fluorescence under LWUV excitation. Akoya and freshwater cultured pearls, which are rou- tinely processed, typically show strong bluish white fluorescence.
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.
Saltwater pearls do not fluoresce, while freshwater pearls do. With all of the varieties of pearls and their differences in value, it is critical to have a way to look below the surface of the pearl. X-rays provide a wealth of information and can reveal the true origin and value of a pearl.
The Vinegar Test
A real pearl will dissolve in vinegar or show erosion where the vinegar drop meets its surface. This is because of the chemical reaction between the acid in the vinegar and calcium carbonate, the primary chemical that a real pearl is made of.
On the other hand, fake pearls are typically made out of glass or plastic and don't contain these natural organic compounds. As a result, they won't display fluoresce under UV light.
Look for tiny irregularities
In a strand of cultured pearls, you can always see very tiny differences between them, even when they are top quality and well matched. If the pearls are completely perfect and identical in terms of shape, size, colour and surface characteristics, they are probably fake.
The qualities that determine the overall value of a natural or cultured pearl or a piece of pearl jewelry are size, shape, color, luster, surface quality, nacre quality, and—for jewelry with two or more pearls—matching.
THE TOOTH TEST
Rub a pearl lightly along the biting edge of your upper front teeth. If it feels slightly rough, sandy or gritty, it's likely a cultured or natural pearl. This texture you feel is the layers of nacre that have formed over time. If the pearl feels smooth or glassy, it is likely an imitation.
Real pearls vary in weight depending on size and type. Generally, they are light but range from 0.5 to 6 grams. Akoya, South Sea, and Tahitian pearls are heavier than freshwater pearls. Larger pearls will also be heavier than smaller ones of the same type.
Natural diamonds have a property known as fluorescence. This phenomenon enables diamonds to produce glows of varied colors when exposed to black light (also known as ultraviolet light). A pure and natural diamond is known to produce a blue glow when exposed to black light.
Keep pearls away from direct sunlight to prevent damage from UV rays. Extreme heat can dry out your pearls leading to discoloration or brittle nacre, which can eventually cause cracking.
Usually fluorescence is blue in color. Less often, a diamond can have yellow or even white fluorescence (other colors too). Diamonds with Strong - or Very Strong - fluorescence can appear quite cloudy, milky or hazy to the naked eye, and emit a prominent and saturated glow in the presence of UV light.
Due to their rarity and the difficulty of collecting them, they were considered more valuable than gold. The value of pearls depends on many aspects, such as: size, shape, color, luster, surface smoothness, transparency, and if you buy more – their price is also influenced by the fit and similarity of each piece.
Fake pearls only shine on their surface and their luster has no depth. Uniformity: A fake pearl necklace, for example, will have pearls that are all the same size and perfectly spherical. In addition, they won't have any blemishes or imperfections when examined very closely.
The most common color for pearls is white, cream, pink, purple, but they also come in colors such as champagne, chocolate, blue, gold, silver and lavender.
(Be aware that water can remove the top layer of imitation pearls). Put pearls on last. Perfume and body lotion can affect a pearl's luster; make sure you apply them before you don your pearls. If you wear pearls regularly, have them checked by a jeweler every six months to a year.
Undoubtedly pearls are prized as intrinsically beautiful objects because of their luster, color, shape, and silky surface, however it is the unique properties of pearls and their ability to reflect and refract light that underline the prevailing belief of pearls as the queen of gems.
Pearls are organic gemstones that are vulnerable to acid, alkaline and extremes of humidity. To preserve your pearls' radiance, avoid letting them come into contact with cosmetics, hair spray, or perfume. Always put on your jewelry as a final touch, after applying make-up and styling hair.
Jones found that a 5 percent solution of acetic acid, a concentration identical to that of white vinegar sold in supermarkets today, takes 24 to 36 hours to dissolve a pearl weighing approximately one gram. The process leaves a small amount of translucent, gel-like material on the surface.
Pearls do not melt at any temperature, the organic part burns before the inorganic part melts. The calcium carbonate in pearl can dissolve slowly in vinegar, the organic part is quite resistant. Vinegar is likely to damage pearls but not easily dissolve them completely.