Pearls are the only gemstones made by living creatures. Mollusks produce pearls by depositing layers of calcium carbonate around microscopic irritants—usually a grain of sand, as it’s commonly believed—that get lodged in their shells.
Appropriately, the name “pearl” comes from the Old Frenchperle, from the Latin perna meaning “leg,” referencing the leg-of-mutton shape of an open mollusk shell. Because perfectly round, smooth, natural pearls are so uncommon, the word “pearl” can refer to anything rare and valuable.
The finest pearls have a naturally reflective luster, making them appear creamy white with an iridescent sheen that casts many colorful hues. Cultured freshwater pearls can also be dyed yellow, green, blue, brown, pink, purple, or black.
Black pearls—which are mostly cultured because they are so rare in nature—aren’t actually black but rather green, purple, blue, or silver.
Today, most freshwater cultured pearls come from China. South Sea pearls are cultured along the northwestern coastline of Australia, the Philippines, and Indonesia.
June’s vegan birthstone, moonstone, was named by the Roman natural historian Pliny, who wrote that moonstone’s shimmery appearance shifted with the phases of the moon.
The most common moonstone comes from the mineral adularia, named for an early mining site near Mt. Adular in Switzerland that supplied this gemstone. This site also birthed the termadularescence, which refers to the stone’s milky glow, like moonlight floating on water.
Moonstone is composed of microscopic layers of feldspar that scatter light to cause this billowy effect of adularescence. Thinner layers produce a bluish sheen, and thicker layers look white. Moonstone gems come in a range of colors spanning yellow, gray, green, blue, peach, and pink, sometimes displaying a star or cat’s eye.
Moonstones are also found in India, Australia, Myanmar, Madagascar, and the United States. Indian gemstones, which are brown, green, or orange in color, are more abundant and affordably priced than their classical blue counterparts.