Gems From the Ocean: Unique Treasures Found Beneath the Waves

Imagine walking along the sand with the ocean stretched out in front of you. The water sparkles all the way to the horizon and somewhere beneath those waves, real treasure is forming. We tend to think of gemstones as something pulled from deep inside the earth, but the sea is a jeweler all its own.

The ocean is more than a vast stretch of blue water; it is a living, breathing treasure trove. Beneath the surface, it grows and guards some of the most fascinating gems in the world: pearls, coral, amber, ammolite, and even diamonds. With June just around the corner (and its birthstone, the pearl, born in the sea), there is no better time to explore the jewels the ocean gives us. Here are five of our favorites, along with a few fun facts you can share the next time you're admiring something sparkly.

Marine Diamonds: The Deep-Sea Resident

This one surprised even us. Diamonds are so closely associated with deep, earth-bound mining that very few people realize the ocean floor is also a diamond source.

Along the coast of Namibia, marine diamonds are actively recovered from the seabed. Their story begins far inland and millions of years ago: formed deep in the earth's mantle, these diamonds were carried by rivers, most famously the Orange River, all the way to the sea, where they settled into ocean-floor sediments over time. Because only the toughest stones survive that long tumbling journey, marine diamonds are often exceptionally high in quality.

FUN FACT: The long trip from mountain to riverbed to seafloor acts like nature's quality filter. Weaker, flawed diamonds break apart along the way, so the ones that reach the ocean tend to be remarkably clear and durable.

Baltic Amber: Ancient Sunlight from the Sea

Amber is not a stone at all, it is fossilized tree resin, and the most prized variety in the world comes from the Baltic Sea.

Tens of millions of years ago, the floor of the Baltic region was a vast forest. Sticky resin oozed from those ancient trees, hardened, and was eventually buried beneath the seabed. Today, that resin, now warm, golden amber roughly 40 to 50 million years old, works its way loose, "pops" up from the ocean floor, and washes ashore for beachcombers to find. (The Baltic Sea in its current form is only about 13,000 years old, which makes the amber within it almost unimaginably ancient by comparison.)

A favorite legend from Lithuania: The sea goddess Jūratė lived in a glittering palace of amber beneath the waves and fell in love with a mortal fisherman. Perkūnas, the god of thunder, was furious that a goddess would love a human, and hurled a bolt of lightning that shattered her underwater amber palace. To this day, the pieces that wash up on the shore are said to be fragments of her broken home.

Red Coral: The Living Gem of the Deep

Unlike most gems, coral was once alive. It is an organic gem, built by tiny sea animals called coral polyps. These creatures form colonies and create hard calcium-carbonate skeletons, which over time build the coral reefs we know. Red coral jewelry is crafted from the dense skeletons of deep-sea coral, polished into rich, warm reds and pinks.

Several hundred species of coral are found around the world, but most of the material used in fine jewelry comes from the Mediterranean Sea, Japan, and parts of India.

Coral has been treasured as a protective talisman for thousands of years. Romans hung coral around their children's necks to guard them from harm. Native American traditions associated it with joy, and in medieval Italy, people believed wearing coral could protect them from the "evil eye."

Ammolite: Canada's 70-Million-Year-Old Rainbow

If you love color, ammolite puts on a show. This rare gem flashes a shifting rainbow of reds, greens, golds, and blues that seem to move as the stone turns in the light, and no two pieces are ever alike.

That dazzling effect comes from extremely thin layers of aragonite within the fossilized shell. As light bounces off those microscopic layers, it splits into shimmering, ever-changing color. Ammolite is a breathtakingly rare organic gemstone, more than 70 million years old, formed from the fossilized shells of ancient squid-like marine creatures called ammonites. It is found almost exclusively in the Bearpaw Formation of southern Alberta, Canada.

FUN FACT: Ammolite is so unusual that the World Jewellery Confederation (CIBJO) officially recognized it as a gemstone in 1981, making it one of only three gems granted that status in the last 300 years. In 2022, it was also named Alberta's official provincial gemstone.

Beyond its beauty, ammolite has long been valued for its supposed metaphysical qualities. It was once used in talismans believed to bring luck, protection, and prosperity, and many people still wear it today to encourage balance, creativity, and positive energy.

Pearl: June's Birthstone and the Ocean's Original Gem

No list of ocean gems would be complete without the pearl, and this June, it takes center stage as the month's birthstone.

The pearl holds a special place among gemstones because it is the only one created by a living creature. When a tiny irritant slips inside an oyster or mussel, the mollusk slowly coats it, layer after shimmering layer, until a luminous pearl is born. No cutting or polishing required: pearls arrive from the sea already perfect, with that soft, unmistakable glow.

Timeless and endlessly elegant, pearls suit every age and every occasion, from a first strand of classic studs to a statement necklace passed down for generations. If you are celebrating a June birthday, or simply love the quiet luxury of a pearl, explore our pearl jewelry collection to find a piece that captures the beauty of the sea.

See the Treasures in Person

From diamonds tumbling to the seafloor to pearls grown in a single shell, the ocean creates beauty in ways the land never could. Each of these gems carries a story millions of years in the making, and a little piece of that wonder can be yours to wear. Our team at J. Thomas Jewelers in Rochester Hills would love to help you find the ocean treasure that speaks to you.

Schedule an appointment with our team, or simply stop by. We're always happy to help you find something that sparkles.