Red diamonds are truly exceptional gemstones. Their captivating deep red hue and extreme scarcity distinguish them as among the most sought-after and valuable diamonds globally.
Defining Their Rarity
Red diamonds are among the rarest of all colored diamonds, far exceeding other fancy hues in scarcity. Fewer than thirty true natural red diamonds are known to exist worldwide. Many experienced jewelers and gemologists may never encounter a genuine natural red diamond in person.
The Gemological Institute of America (GIA) did not issue a single lab report for a pure red diamond between 1957 and 1987. This 30-year period without grading any pure red stones underscores their unparalleled scarcity. Most red diamonds discovered are very small, typically weighing less than one carat. The closure of the Argyle mine in Western Australia, a primary source for pink and red diamonds, further limits their supply.
The Unique Origin of Red Color
Unlike most other colored diamonds that derive their hue from chemical impurities, red diamonds obtain their color from a different scientific phenomenon. Yellow diamonds, for instance, get their color from nitrogen, and blue diamonds from boron. Red diamonds, however, are composed purely of carbon, similar to colorless diamonds.
The red color originates from structural anomalies or “plastic deformation” within the diamond’s crystal lattice. This occurs when the diamond is subjected to intense pressure and heat deep within the Earth during its formation or ascent to the surface. Such extreme conditions cause the carbon atoms to shift slightly, altering how light passes through the stone and resulting in the absorption of certain wavelengths and the reflection of red light. The exact mechanisms behind this phenomenon are still a subject of ongoing scientific research and debate.
How Red Diamonds Are Valued
The value of red diamonds is primarily determined by their color intensity and saturation, even more than the traditional “4 Cs” (Carat, Cut, Clarity, Color). While the 4 Cs are factors, the purity and vibrancy of the red hue are paramount. Pure red diamonds, those without secondary hues like brown or orange, command the highest prices due to their extreme rarity and desirability.
Their unparalleled scarcity significantly inflates their market price, making them some of the most expensive gemstones per carat. Red diamonds command prices exceeding $1 million per carat, far surpassing almost any other type of diamond. For example, a 1-carat fancy red diamond can sell for two to three times the price of a 0.50-carat stone of similar quality. This combination of rarity and high demand makes red diamonds highly sought after by collectors and investors.
Iconic Red Diamonds
Several red diamonds have achieved iconic status due to their exceptional size, color, or historical significance. The Moussaieff Red Diamond, weighing 5.11 carats, holds the distinction of being the largest known red diamond in the world. Discovered in Brazil in the 1990s, it was initially a 13.9-carat rough stone before being cut into its current triangular brilliant shape.
Another notable example is the Hancock Red Diamond, a 0.95-carat round brilliant cut stone. This diamond made headlines in 1987 when it sold for $880,000, setting a record for the highest price per carat at the time. The Kazanjian Red Diamond, weighing 5.05 carats, is also among the largest known red diamonds. Its history includes being confiscated by the Nazis during World War II and later rediscovered in a salt mine.