Pearls are one of June's birthstones. Cultured freshwater pearl beads come in several shapes, plus your choice of natural and dyed colors. This means you can add elegance to a wide variety of jewelry designs - pearls aren't just for bridal designs, weddings and proms! Pearls are organic gemstones, formed when a foreign object (like a tiny stone) makes its way into an oyster (or similar mollusk's) shell. Over time, the mollusk covers the intruding object with 1,000's of layers of nacre. "Cultured" pearls are pearls in which people, rather than nature, implant the foreign particle, and care for the mollusks at a pearl farm while the pearls develop. Nearly all pearls available today are cultured. Natural pearls are very rare (and valuable!), so the word "pearl" should be assumed as "cultured pearl" unless otherwise noted. Pearls formed by saltwater oysters are commonly known as oriental pearls and those produced by freshwater mollusks are called freshwater pearls.