Pearls are round, hard masses formed in the shells of most living mollusks. Their lustrous appearance and smooth surface make them a popular addition to women’s jewelry and accessories. While pearls can be found in many shades, including pink and green, white and black are the most commonly used colors. There are eight basic shapes used for jewelry: round, semi-round, pear, drop, button, baroque, oval, and circled. A perfectly round pearl is rare, making it the most valuable. Less expensive options for a similar look are cultured pearls (see below), or imitation pearls, which have close to no value.
Pearl, the June birthstone
The birthstone for June is the pearl. Alexandrite and moonstone are also birthstones for June, however, the pearl is the most popular birthstone used for those celebrating their birthday in June. You can learn more about the history of the pearl, the properties of the pearl, where pearls are found, how to care for pearl jewelry, and the largest pearls found at our June Birthstone page.
How are pearls made?
Natural pearls are made when a parasite enters a mollusk. If the parasite embeds itself into the mollusk’s soft mantle, the mollusk will cover the parasite with a sac and begin to form layers of nacre around the irritant. Nacre is the smooth, shiny substance that makes up the interior of the mollusk, usually an oyster, and over time, the layers formed around the irritant will form a pearl. Today, natural pearls are extremely rare. Only a small percentage of mollusks form pearls—out of approximately the 8,000 different species of mollusks, only about 20 are capable of regularly making pearls. Those that do produce pearls rarely generate stones that are large enough or the proper color to use as jewelry. The thicker the nacre, the more durable and desirable the pearl, which means that time needed for thicker nacre is also a factor. Natural pearls are sold by carat weight.
Nacre definition. What is nacre?
Nacre is the iridescent material that the mollusk forms in very thin layers that creates the pearl. Nacre is composed of hexagonal platelets and elastic biopolymers, which makes the material strong and resilient. The mollusk continues to deposit layers of nacre, which protects the soft tissues of the mollusk and traps parasites inside the layers. This process continues as long as the mollusk lives.