Pearl- This is another birth “stone”. The pearl is sometimes a victim of mistaken identity. It’s not actually a stone, but rather the byproduct of a living organism–the mollusk, and created when foreign debris gets inside its shell, causing the animal to excrete calcium carbonate around the debris. The most common of these animals known for growing pearls is the oyster. But did you know that any shellfish identified as a mollusk can actually grow a pearl, and not all of them are in saltwater? It’s true! Depending on where they are grown (i.e. saltwater, freshwater) depends on their shape, size, and color. These days, most pearls are farmed, meaning humans actually make the animal grow the pearl by inserting either a small bead of the substance known as mother-of-pearl, making them round, except when it comes to freshwater mollusks. Pearls grown in those animals are usually started off with a small bit of tissue, and are often a soft pastel color, whereas saltwater pearls are dark grey or green, and white. That way the pearl is thicker, and more lustrous, but usually misshapen. Natural pearls are rare, and are not always round.