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Cultivating Natural Beauty: Sea of Cortez Pearls

Posted by Catherine Claus on

“All art is autobiographical. The pearl is the oyster’s autobiography.”

Federico Fellini wrote that about his own work in 1965, but it perfectly captures the reason pearls enchant me: They tell the story of their own creation. 

I recently told you about five gems that have captivated me. Now I want to give you a closer look at each one, starting with Perlas del Mar de Cortez, or Sea of Cortez Pearls.


Rare Oysters Make Rare Pearls

Cortez Pearls are the most rare cultured pearls in the world, with only 4000 produced annually.

They display a rainbow of color unlike any other pearl because they are produced by the rainbow-lipped pearl oyster, found only in Baja, Mexico, and northern Peru. The unique pigments created by this oyster include gray, black, pink, gold, green, and purple.

These pearls have all the qualities that I love in gemstones:

  • There is a fascinating history behind Sea of Cortez pearls
  • Science — specifically, ecology — plays an important role in their cultivation
  • They come in unique, iridescent colors
  • And they are one of a few gems that are 100% Fair Trade certified


Glowing From Within 

All pearls have an iridescence that makes them glow without any polishing. That smooth, iridescent surface is actually many layers of nacre: a material produced by pearl oysters (and other mollusks) to coat their inner shell. Oysters use the same substance to coat any irritants found inside their shell. 

Nacre is a composite of thin layers of the crystalline mineral aragonite held together by elastic biopolymers (the same biopolymers found in fish scales). These microscopic layers actually interfere with light to produce what’s called “structural coloration.”

That means when the light hits a Cortez Pearl, the unique pigments naturally found in the biopolymers are refracted through the prismatic layers of aragonite. This creates a luminous rainbow that seems to emanate from within the pearl itself.  



From Conquest to Cultivation

After Spanish conquistador Hernan Cortez invaded Mexico in the early 16th century, Mexican “black pearls” quickly became New Spain's most prized export, valued above gold, silver and spices. European royals like Catherine the Great and Marie Antoinette rushed to wear the so-called “Queen of Gems.”

After several centuries of pearl diving in the Gulf of California, or Sea of Cortez, the oyster population began to dwindle from overfishing. So producers switched to pearl farming, cultivating vast oyster beds that could yield 800,000 pearls a year.

Then, in 1935, the Hoover Dam began operating. The nutrient-rich waters of the Colorado River stopped flowing into the Sea of Cortez, killing off the plankton that oysters feed on. The oysters nearly went extinct.

Fortunately, in the 1990s, a group of marine biologists began to study new, sustainable methods of pearl-culturing. They focused on breeding rainbow-lipped pearl oysters, ultimately moving them off the endangered species list.


The Only Fair Trade Pearl Farm

At Thesis Gems and Jewelry, we source our Cortez Pearls from the Perlas del Mar de Cortez farm in Guaymas, Mexico. This remarkable farm produces a broad color range of black pearls in limited-edition harvests using fair labor practices.

Cortez Pearls are the only fair trade cultured pearl. The farm’s founding marine biologists pledged to protect the environment while producing high quality natural pearls that need no artificial enhancement.

Cortez Pearls are more than pretty gems. As the farmers put it, they are “a concept that integrates the pearl, its history, the environmental protection, and the person” who wears them. These pearls are not only the autobiography of the rainbow-lipped pearl oyster, they tell the story of an entire ecosystem.

Perlas del Mar de Cortez Mabe Pearl and Rhodalite garnet set in reclaimed gold.

Turn Heads with the “Queen of Gems” 

Cortez Pearls are a favorite of mine to wear because their lustrous colors are truly organic and they shine without cutting or polishing. Holding one reminds me of their vivid and volatile 400-year history, as well as their present day story of restoration and redemption.

If you’re interested in adding a Cortez Pearl to your jewelry collection, reach out today. I can help you find or design a piece you’ll treasure for a lifetime.