In this article, we’re going to talk all about pearls. So, pearls have been revered for thousands of years across the globe. They’ve gone up and down in value with the advent of the culturing process, giving pearls availability to all sorts of people, not just the Cleopatras and Mark Antonys of the world.
But what’s the difference between a natural pearl and a cultured pearl, and what are some of the imitations that you can see on the market? We’re going to talk about all of that today.
Let’s start with the natural pearl. This would have been the first pearl that mankind ever discovered. No synthesizing processes, no culturing processes.
Early ancient man diving down for scallops or mussels or something to eat cracks them open on the shore, and boom, inside is a gleaming white spherical gemstone. How did it get there? Where did it come from? Are there more? Should I go back? Ancient man had no idea where the pearls came from, but we do know today.
How A Pearl Is Formed?
So here’s how a pearl forms: an irritant gets into the shell of a mollusk, usually a bivalve like a mussel or a scallop, which just means it opens and closes like a book. A little irritant gets in there, and the mollusk starts to coat the irritant (grain of sand, fragment of shell) with a layer of nacre.
So this substance, nacre, is made of aragonite, which is a calcium carbonate. Because of the culturing process, pearls are available to all kinds of people, and they are graded based on a number of criteria.
The Luster Of A Pearl
So, let’s break it down. Firstly, there’s the luster of a pearl. This luster is given the unique name of pearlescent luster. Very creative. It basically just describes that unique luster on the surface of a pearl, both natural and cultured. And the better the luster on the pearl, the sharper the light reflects off of the surface of it.
The Diameter Of A Pearl
Pearls are also valued by size, and the diameter of a pearl is measured in millimeters. So, the larger the pearl, the more valuable.
The Shape Of A Pearl
The shape of a pearl is also taken into consideration.
So we start on this end with a round. This is more or less perfectly spherical. Off-round, you start to get a little bit of asymmetry in your pearl shape.
Oval, which is where it sort of stretches out but is still rounded and nice. Semi-baroque is where you start to get into the territory of lumpy or oblong.
And then, Baroque is like free form, very interesting shapes, nothing very spherical about it, but it makes for very interesting and dynamic jewelry, for example.
The Surface Conditions Of Pearl
Next, we also consider the surface conditions of our pearl. As few blemishes as possible on the surface of the stone are more desirable.
The Color Of A Pearl
And then we have the color of a pearl. This color is going to be affected by the inner lining of that host mollusk’s shell. The color of a pearl overall is considered to be a combination of body color and overtone. So, the body color of a pearl can be white, black, pink, kind of cream, and the overtones on the body can be pink or rosy, green or blue, and even a little bit of silver.
What Is A Cultured Pearl?
Let’s move on to cultured pearls. So, cultured pearls make up about 95% of the pearls on the market.
Basically, a cultured pearl forms more or less the exact same way a natural pearl does, except a farmer initiates the process. Someone implants either a bead nucleus or a little fragment of shell or some tissue into the mollusk, by force, forcing the mollusk to start secreting nacre and coating this little bead.
Cultured Pearls vs Natural Pearls
We have natural pearls and we have cultured pearls, but how do we spot the difference?
We’re going to show you guys a few techniques just using your naked eye. A 10x loop and a little bit of clever lighting, let’s work from the outside in.
The surface of a cultured pearl is going to be a little bit smoother, a little bit rounder, and with fewer imperfections compared to a natural pearl, which is going to have some slight bumps and may not be as smooth or round as a cultured pearl.
In a cultured pearl, look for consistent color and luster, whereas in a natural pearl, you may see some inconsistent color and a few patches in the luster.
If the pearl was being used as a bead, then it’s going to have two drill holes in it, and that’s where we’ll look next. In a cultured pearl, the nacre near the drill hole should look a little bit thin, and if you look down in there, you could see the nucleus from which the pearl was formed.
Whereas in a natural pearl, if you look down into the drill hole, you may see concentric growth lines, which would be indicative of a very slow natural aqueous formation process, kind of like the growth lines in a tree. Also, the nacreous layer near the drill hole will be a little bit thicker than in a cultured pearl.
The more perfectly symmetrical and spherical a pearl is, the more likely it’s a cultured pearl, whereas natural pearls tend to be a little bit more irregular and asymmetrical, as well as outright different shapes like Baroque or semi-Baroque.
This next technique is called candling, and we need a dark space and a flashlight. This technique is especially good for identifying cultured pearls, and it involves shining a light through the pearl to see the internal structure of it.
So, you’re going to want to take a strong light source like a flashlight or a lamp, and you want to do this in a dark room so you can get the most contrast between your backlit pearl and the ambient light around you.
When you’ve got your pearl backlit in a dim environment, look for a couple of things that we just talked about to be reinforced: a very thin nacreous layer in a cultured pearl versus concentric growth lines like the rings of a tree in a natural pearl. You can also look for small flaws and irregularities within the center of the pearl, indicating a natural pearl.
Let’s talk about imitations. To imitate a pearl, typically beads of glass or shell or plastic are coated with a material that sort of resembles the luster of nacre.
But, like with our natural pearls, we’re going to take a look at the drill hole in our imitation pearl and see what we can find.
On an imitation pearl, you’re going to see a thickening of that imitation nacre layer right around the drill hole. It’s going to clump up and be a little bit uneven. The surface of one of these imitation pearls will also appear a little bit more granular and rough in surface texture than a natural or cultured pearl, and this is due to the imitation material that they coated it with.
This last test is a little bit more hands-on and should maybe be a last resort if you can’t quite tell what you’re looking at. But if you take a natural or cultured pearl and you rub it on your teeth, it will feel granular and rough.
But if you take one of these imitation ones and rub that on your teeth, it will actually feel smooth. So, if you’ve got a drill hole and you’re looping it and you can’t quite tell what you’re looking at, give it a rub—just rub it on your teeth—and you might find out what you’re looking for.