Cortez Pearl

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June Birthstone

Emerging once more from the clear waters of the Gulf of California, after decades of protection, is Mexico's most emblematic gem: 'New World Black Pearls'. In 1533, the Spanish Conqueror Hernan Cortez sent the very first expeditions into the area to find the mythical "Sea of Pearls." Soon, the area known as the "Vermillion Sea of Cortez" - that we officially know as the Gulf of California - produced one of the finest known pearls in the world, the Cortez Pearl. These prized gems became New Spain's most important export product, with a price so high that their value was more than double of that of all other combined exports to the Old Continent: gold, silver and spices. It was at this moment in time when Mexican black pearls came to be known as the 'Queen of Gems' and the 'Gem of Queens', adorning European nobility like never before. Back from a 400 year reign and near extinction, are a new generation of Cortez Pearls being cultivated from the same highly-priced oysters of Mexico.

Cortez Pearl Polished
Cortez Pearl Classification
Common Name Cortez Pearl
Species Pearl
Cortez Pearl Optical Properties
Transparency Translucent - Opaque
Refractive Index 1.530-1.685
Birefringence 0.155
Polariscope Reaction Aggregate (AGG)
Fluorescence SWUV:
LWUV: Black pearls will fluoresce hot pink to magenta
Pleochroism None
Cortez Pearl Characteristic Physical Properties
Hardness 2.5-4
Specific Gravity 2.720-2.780
Toughness Good
Luster Dull, Metallic
Stability Poor
Fracture Uneven
Cleavage None
Cortez Pearl Chemistry & Crystallography
Chemical Name calcium carbonate + conchiolin and water
Chemical Formula CaCO3
Crystal System NA
Chemistry Classification Organic

Cortez Pearl Colors

  • Brown Cortez Pearl Brown
  • Purple Cortez Pearl Purple
  • Gray Cortez Pearl Gray
  • Blue Cortez Pearl Blue
  • Black Cortez Pearl Black
  • Yellow Cortez Pearl Yellow
  • Green Cortez Pearl Green

Alternate Names

Rainbow Pearls

Countries of Origin

Mexico; Madagascar

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Tim Matthews


Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.