Cortez Pearls®

Cortez Pearls® are rare saltwater cultured pearls from the rainbow lipped Pteria sterna oyster, native to Mexico’s Sea of Cortez. Pearls are organic gems, created when a mollusk covers a foreign object with beautiful layers of nacre, the mother of pearl. Cultured pearls are the result of the work of both man and mollusk: a skilled technician inserts a shell bead in the oyster to encourage the oyster to form a pearl. The results are nothing less than amazing!

Can you tell us a little about the source of this material?

These pearls are cultured in the waters of Bacochibampo Bay in the Sea of Cortez, near the city of Guaymas, Mexico. They are harvested once a year around June to early July.

The pearl oysters are checked on a regular basis to determine just when to harvest. Water temperature also help decide the optimal harvest date. Harvesting at just the right time means the pearls will display their maximum natural luster. When the pearls are harvested, they go directly into a bath of fresh water. There are no treatments used. The oysters themselves are sold to local food markets and shells used to back their famous Mabe pearls. This helps to produce sustainably without waste.

What kinds of sizes, shapes and cutting styles can be found?

Cortez Pears® can be found in 3 different shapes: Semi-round, baroque and mabes. Mabes can range in size and surface texture, some defined as ‘blister’ mabes. Semi-round and baroque shaped Cortez Pearls® are commonly found in 8 to 10.5mm sizes but some rare Cortez Pearls® are as large as 12mm!

Is this material typically enhanced in any way?

These special cultured pearls are never treated in any way. Once harvested, these pearls are simply dropped into a bath of fresh water to clean away any residue left from the harvesting process.

Are there any unique characteristics you can share about this material?

Since these pearls are not treated, there are a unique set of characteristics that we look at while grading them. These include size, shape, luster, surface texture and color. Each Cortez Pearl® is truly a one-of-a-kind piece, which means you will find a wide variety of individuality. You may find what we refer to as ‘GEM’ quality luster, which we define as exceptional in sheen, color complexity and depth of luminosity. Or you may find what we refer to as AA quality luster, which is a significant or noticeable sheen with a moderately complex color range and luminosity. When looking at surface textures, we evaluate how smooth, bumpy, ringed or pitted each pearl is.

Then there’s color. Color is really the magnificent part of these pearls. From peacock colors to blacks, bronzes, greens, blues, pink-reds, whites and silvers – there is no wonder why the oysters these pearls come from are referred to as the ‘rainbow-lipped oyster.’ When grading, color is evaluated by identifying the primary, secondary and tertiary colors because often times there will be multiple colors visible at a time.

One of the most fascinating and distinguishing characteristics of Cortez Pearls® is the distinctive rose-red fluorescence when under ultraviolet light. This is the only pearl that fluorescence this color and is an assurance that you have a genuine Cortez Pearl®. While some fluoresces more than others, they each react to the ultraviolet light. Click here to watch a video of what this looks like on our Instagram page.

What are the gem specs of this material? How do we know if it is authentic?

The material we source at Columbia Gem House is backed with our Gem Trust guarantee. This means you know it’s an authentic gemstone and that we will share all available information with you. You can find additional gem specifications below:

Gem Type
Cortez Pearl®
Fair Trade Level
Sea of Cortez
Not Treated
Hardness (Mohs Scale)
2.5 to 4
Very Good; Varies by Pearl

How do I care for my gemstone?

Pearls are organic and must be protected from chemicals and oils. Always put pearls on after applying lotions, perfume, cologne, make-up, or hair products. Before putting your pearls away after wearing them for the day, wipe them with a soft cloth to remove dust or oil. Store them in a cloth-lined box or pouch and keep them away from other jewelry, which might scratch them. It is best not to put your pearls in an ultrasonic or steam cleaner.

What can you tell us beyond the facets? I want to know more…

Spanish captain Fortun Jimenez admired the pearls he saw local people wearing when he visited what he called the "Sea of Pearls" in 1533. Natural pearls were harvested from these waters for the next 300 years, becoming an important export. Unfortunately, the construction of the Hoover Dam depleted nutrients in the Gulf of California, diminishing natural pearl production in the area. To protect the oysters, the government banned harvesting of natural oyster beds in 1939. The Monterrey Technical Institute in Guaymas began studying pearl culturing in 1993, producing the first experimental round pearls in 1996. Only 4,000 pearls are cultured in these waters each year, making them the rarest of cultured pearls. Less than 30 percent of the production is round.