The Rarest Diamond Color On Earth & Why It's So Valuable

rarest diamond colors - red diamond in tweezers with other colored diamonds on the table

When you are shopping for diamonds, your most powerful tool is knowledge. Diamonds are the world's most popular precious stone, so most people are already familiar with the 4Cs (color, cut, carats, clarity). But what if you want something a little more unique than your traditional white diamond?  

Here we delve into the rarest diamond colors, the most precious colored stones in the world, and explain diamonds get their unique colors. 

Let’s get right to it...

Quick answer: The rarest diamond color is the red diamond. They are so rare that less than 30 true red diamonds are known to exist. They can cost $1 million per carat and most of the red diamonds in existence are less than ½ a carat in size. 

A DIAMOND’S VALUE

A diamond’s value is mainly determined by its ratings in the 4C’s, but ultimately the most important rating is your own. Your diamond can have a symbolic meaning to you that justifies a higher price or a story that connects you to something or someone. 

But when you're shopping around, here’s a way to help you narrow down the field:

  • decide which 4C matters most (size/carats, color, clarity, cut)
  • find stones that rate high in that C
  • average out the remaining Cs for each stone
  • consider the diamonds with the highest overall 4C averages.

Here are the 4C’s in depth...

Color 

The Gemological Institute of America (GIA) sets the worldwide standard for the color-grading of diamonds. Colors are graded D through Z. D is colorless, while Z has yellow or brown tones.

Carat weight 

One carat is the average weight of a carob bean.

Clarity

This C measures the amount of inclusions (other materials)on a  6-point scale at 10x magnification.

  1. FL (Flawless)
  2. IF (Internally Flawless)
  3. VVS1 and VVS2 (Very, Very Slightly Included)
  4. VS1 and VS2 (Very Slightly Included)
  5. SI1 and SI2 (Slightly Included) and
  6. I1, I2 and I3 (Included)

Cut

The most common type of cut is the Round Brilliant cut. Other popular cuts include Rose, Asscher, Hearts and Arrows, and Modified Brilliant (in Pear, Heart, Marquise and Triangular shapes).

Other factors can also affect the overall value of diamonds. These include:

  • Fluorescence
  • Shape
  • Symmetry
  • Girdle
  • Pricing
  • Culet
  • Certification
  • Polish

Types Of Diamonds Based On Their Color

  • More Affordable Pricing - Grey, Brown, and Fancy Yellow Diamonds
  • Mid-Range Pricing - Intense and Vivid Yellow Diamonds and Orange Diamonds
  • High-Range Pricing - Pink, Purple, Violet, Green, and Blue Diamonds
  • Very High Pricing - the rarest diamond color: Red

Intensity refers to a stone's level of color saturation. It adds another layer of value. There are nine grades in the intensity scale:

  • Faint
  • Very Light
  • Light
  • Fancy Light
  • Fancy
  • Fancy Intense
  • Fancy Vivid
  • Fancy Deep
  • Fancy Dark

WHY ARE SOME DIAMONDS DIFFERENT COLORS?

Each natural color has its own perfect storm of minerals, ambient pressures and temperatures, incubation time (usually eons), gases, elements and other factors as the diamonds form deep within the earth.

Diamonds are scientifically classified as either Type I or Type II, depending upon whether nitrogen is present, and how it is configured within the matrix.

Type I Diamonds

Types IaA and IaB comprise around 98% of all gem diamonds; IaA are largely found in Cape Province, South Africa while IaB are found in Buffalo Hills, Namibia, and Eurasia. The nitrogen atoms are paired in the matrix of Type IaA diamonds and clustered in Type IaB. Pure Type IaB diamonds are very rare because they usually mix with Type IaA in the same stone.

Type II Diamonds

These are the most sought by collectors and investors. Type IIA are chemically the purest, with no measurable nitrogen or boron impurities. Type IIB contains no nitrogen but does contain boron.

THE RAREST DIAMOND COLOR

RED DIAMONDS

red diamond on white gold ring

The exact processes that create red diamonds still remains a mystery. They are generally thought to involve a process called plastic deformation that distorts their molecular structures.

Plastic deformation occurs deep below the earth's surface, where temperatures are extremely hot and pressures immense. Tremendous forces work newly-formed diamonds like dough until some of the outer atoms come out of the lattice and slide to a different row where they reattach themselves, causing deformations that refract light to manifest red.

relationship between pink and red diamonds has been noted. While red diamonds are not always discovered with pink ones, pink diamonds have always been discovered with red.

Red diamonds come from Africa, Brazil, and Australia. The Argyle Mines in remote Kimberley, Northwestern Australia produced pink, purple, and red diamonds from 1983 until they closed in 2020.

Red diamonds fall into the IIa and Fancy categories. Only about 30 real natural red diamonds have been found. Prices between two equally-rated red diamonds can differ up to 60% per carat, even if the red is secondary. As a result, they can cost 300% to 400% more than the most expensive colored diamonds.

Two of the most famous red diamonds are the Moussaieff Red and the Hancock Red.

THE MOUSSAIEFF RED is the largest red diamond in the world, weighing 5.11 carats and graded Fancy Red IF. It was known as the Red Shield Diamond until it was bought in 2001 by Shlomo Moussaieff, an Israeli dealer from London. At $1.6 million per carat it is among the top 10 most expensive diamonds in the world.

THE HANCOCK RED, formerly known as the Halphen Red, is a .95 carat Fancy Purplish-Red Brazilian diamond worth $926,315 per carat. Bought for $13,500 in 1956, it became famous in 1987 when it was sold for $880,000 at auction. It was the first gem-quality stone ever to be sold at auction.

BLUE DIAMONDS: THE SECOND RAREST COLOR

blue diamond rings

Blue diamonds come from Australia, South Africa, and India. They are pushed from deep underground to the surface by little volcanoes called Kimber. They owe their color to the presence of boron and/or hydrogen.

Rated Type IIb Fancy, their grading scale ranges from Faint Blue to Fancy Dark Blue, and most have a secondary hue. A greyish-blue diamond can cost 1/7 of the cost of a Fancy Intense blue diamond of identical weight.

Some blue diamonds are electrical semiconductors rather than electrical insulators.

THE HOPE DIAMOND

Mined in India and graded Fancy Dark Grayish-Blue, its estimated value is $200 to $350 million. Cut in 1668 stolen and recut in 1792, its largest remaining section (45.52 carats) was named after the Hope family of London. In 1958 it became part of the American Natural History Museum's permanent exhibit.

THE BLUE MOON DIAMOND

This diamond sold in the rough for $25.6 million, producing a 12.03 carat fancy vivid IF blue diamond valued at $4 million a carat. Because it also ranked top in color and clarity it was called the Blue Moon Diamond. Hong Kong billionaire Joseph Lau bought it for his seven-year-old daughter at $48.5 million, making it the world’s most expensive diamond, and renamed it the Blue Moon of Josephine

THE WITTELSBACH GRAFF DIAMOND

The Wittelsbach Graff Diamond once belonged to the crown jewels of Austria and Bavaria. Ten years after being displayed in the last Bavarian king's funeral it disappeared after an auction at Christie's in London. It was exhibited, unrecognized, at the Brussels World Exhibition in 1958.

In 2008 Lawrence Graff, a London jeweler bought it for $23.4 million. Despite the furor, recutting it took it from a slightly scratched 35.56-carat Fancy Deep Grayish-Blue VS1 to a 31.06-carat Fancy Deep Blue IF.

People have speculated that both diamonds may have come from the same rough stone that was split by Louis XIV.

YELLOW DIAMOND: MOST COMMON COLOR

yellow canary diamond ring

Yellow diamonds get their color from nitrogen during formation. All it takes is a 0.10% concentration within the matrix!

Canary yellow is the most yellow-saturated and most-sought yellow diamond. The difference between fancy, intense, and vivid yellow diamonds lies in their positions along the grading scale.

Yellow, the commonest fancy color, makes these diamonds overall the least costly at about $6,500 to $8,000 per carat.

PINK DIAMONDS

pink diamond

Lacking impurities, pink diamonds get their color through plastic deformation, as do red diamonds. There is also evidence of electron transfer between defects within the structure.

Pink diamonds have trace nitrogen and boron. They are found in Brazil, South Africa, and Australia. Prices average between $10,000 and $700,000 per carat.

THE GRAFF PINKTHE PERFECT PINK, a Fancy Intense pink diamond, weighs 14.23 carats. It sold in 2010 at Christie's in Hong Kong for 18,996,100 in US dollars.

THE STEINMETZ PINK, now known as THE PINK STAR DIAMOND, is the largest known Vivid Pink diamond ever rated, at 59.60 carats. It was bought at $83,187,381 in 2013.

ORANGE DIAMONDS

orange diamond stud earrings

Orange diamonds get their color from the incorporation of nitrogen mineral atoms into the lattice.

Orange diamonds are rare, especially those without secondary color.

THE PUMPKIN ORANGE DIAMOND

Like the Moussaieff Diamond, the Pumpkin Orange Diamond was found by a South African farmer, indicating that it may have been found in a river. Estimated at $3 million, this Fancy Vivid Orange cushion-shaped diamond weighs 5.54 carats.

GREEN DIAMOND

green diamond earrings

Diamonds turn green through irradiation. Green diamonds contain the minerals nitrogen, hydrogen, or nickel and are among the rarest fancy-color diamonds. They come from India, Africa, and South America.

Because green diamonds are caused by radiation in the soil, the green layer is often a shallow layer sitting on top of the diamond. Green diamonds with the color all the way through are extremely rare and sell for millions of dollars at auction

THE DRESDEN GREEN DIAMOND

Internally flawless at 40.70 carats, the rare and beautiful pear-shaped Dresden Green Diamond came from India. The earliest record of it appeared as a London newspaper article dated 1722. It now sits in the Albertinum Museum in Dresden.

OCEAN DREAM DIAMOND

Gorgeous, 5.50 carats, and extremely rare, this triangle-cut SI1 Fancy Vivid Blue-Green diamond was found in Central Africa. Now owned by Cora Diamond Corporation, its value is between $7.5 and $10 million.

BLACK DIAMONDS

black diamond pendant

Popular with men, black diamonds, which contain graphite, come from Central Africa and Brazil. They are opaque.

Artificial enhancement is achieved by burning the rough stone to blacken it. Natural black diamonds are rare but cost less than color diamonds.

BROWN DIAMOND: MOST COMMON COLOR

chocolate brown diamond ring

Sometimes called chocolate diamonds, brown diamonds get their color from irradiation, nickel, and trace nitrogen minerals. They are the most affordable besides black and the most common besides yellow, accounting for 15% of all diamonds.

RAREST WHITE DIAMONDS

Often referred to as Super D or C grade, Type IIA white diamonds contain neither nitrogen nor chemicals and are whiter than typical white diamonds. In the Fall of 2020 Sotheby's offered a Flawless strawberry-sized 102.39-carat white diamond for auction that sold for $15.7 million.

Sotheby's 102 carat white diamond

As you can see, there is a lot to know about diamonds--in fact, what we have discussed here has barely scratched the surface. But now you know, if you come across a red diamond for a bargain, get it!