Birthstone of the Month: June

Pearl in shellJune’s birthstone is one that stands apart from the crowd. It’s the only birthstone that’s formed by a living organism rather than the usual geologic processes that form other gems. Emerging self-complete and pristine from the rough shell of a mollusk, the pearl’s beauty has a special magic admired since the most ancient times.

The world’s religious literature is rich with references to the pearl, and fantastic legends have evolved to explain its origins. Above all pearls are associated with womanhood, healing, purity, and innocent beauty.

Image: (Thomas Northcut/Digital Vision/Getty Images)

Birth of a pearl

Pearls form when an irritant or injury inside the mollusk’s shell is covered by layers of nacre, the same substance known as “mother of pearl.” Nacre is made of a chalk compound that is deposited in microscopic layers. Chalk by itself is very brittle, so it takes bio-polymers secreted by the mollusk to coat and bind these fragments into an extremely dense and durable material. Pearls come in a dazzling variety of shapes and colors depending on the environment in which they form.

Saltwater vs. Freshwater

Freshwater pearl mussels can live in waters all over the world, while the famous saltwater pearl oysters thrive in warm tropical waters. Most pearls in the jewelry market originate from South and East Asia and Australia.

Natural vs. Cultured

Natural pearls are those which have been harvested from the wild. Composed of up to 90% pure nacre, they are extremely rare today and very valuable. Cultured pearls are from shellfish raised in a controlled environment, with a nucleus or bead precisely placed within the mollusk’s shell to promote the formation of a pearl. Lesser-quality pearls are mostly implant, with only a thin veneer of nacre. The origin of a pearl is easily determined by x-ray.

Pearl Colors
Image: The Pearl Market

Choosing the right pearl

When choosing pearls, remember that their luster or inner glow should be irresistible – after all, they’re the moon’s teardrops! Equip yourself with good information and be sure of the quality of the product before you buy.

Pearl care

Durable as they are, pearls are composed mostly of chalk – which means anything acidic is an enemy. (In fact pearls will dissolve in vinegar!) They require only the gentlest of cleaning, so polish them frequently with a soft cloth. Store them safely by laying them flat on a soft surface. Never wrap them in plastic – pearls are organic and need to breathe!


An alternate birthstone for June is the moonstone, a type of feldspar. Like the pearl, it has a radiant, iridescent quality that ancients believed could confer good health, wisdom and victory. Moonstone makes an excellent June birthstone for the man on your list!

Jewelry Information Center: Pearls
EarthSky: June Birthstones