Yes, colored diamonds occur naturally and are considered real diamonds. Diamonds come in a variety of colors beyond the typical clear or white. Colored diamonds get their coloring from chemical impurities and structural defects in the diamond crystal lattice during their formation. The most common diamond colors are yellow, brown, pink, blue, green, and black. These colorful diamonds are very rare, making up only about 0.001% of mined diamonds. Their rarity increases their value significantly compared to clear diamonds.
How do diamonds get their color?
Diamonds get their coloring from chemical impurities or structural defects in the crystal lattice during their formation deep underground billions of years ago. Different chemical impurities or defects result in different diamond colors. Here are the main causes of color in natural diamonds:
Nitrogen impurities
Nitrogen is the most common impurity found in diamonds. When nitrogen atoms are clustered in groups within the diamond, they absorb light in the blue end of the spectrum, causing a yellow or brown tint. The more nitrogen present, the more intense the color saturation. Nearly all yellow and brown diamonds get their color from nitrogen impurities.
Lattice defects
Defects in the crystalline structure like missing carbon atoms, dislocations, or irregular bonding can also impact color. These defects absorb light across the color spectrum, resulting in pink, red, purple, gray, or brown hues. The most famous colored diamond, the Hope Diamond, owes its rare deep blue color to lattice defects.
Hydrogen impurities
When solitary hydrogen atoms are present in a diamond, they cause a bluish-green tint. This coloration from hydrogen is rare. The vivid green of the Dresden Green Diamond comes from hydrogen impurities.
Radiation exposure
Exposure to radiation can also turn some diamonds green, blue, brown, pink, or yellow. Diamonds contain trace uranium impurities. As the uranium decays, it releases alpha particles and protons that interact with the diamond and alter its atomic structure, producing color centers.
Plastic deformation
Intense heat and pressure can cause plastic deformation where carbon atoms shift out of position. This deformation creates irregularities in the crystal lattice, leading to pink, red, brown, or yellow colors. Plastic deformation is the cause of color in most pink diamonds.
What are the different natural diamond colors?
While colorless and near-colorless diamonds are most common, colored diamonds come in a full spectrum of vibrant hues. Here are some of the main natural colors that diamonds exhibit:
Yellow
Yellow is the most common fancy diamond color. As mentioned earlier, yellow comes from nitrogen impurities clustered within the diamond crystal. The more saturated the yellow, the higher the concentration of nitrogen. Canary yellow diamonds are rare and prized. Yellow diamonds also often exhibit a secondary color, like brownish-yellow.
Brown
Brown diamonds also owe their color to nitrogen impurities. Increased levels of nitrogen result in darker brown hues. The most desirable brown diamonds have rich chocolate or cinnamon tints. Brown is among the most affordable of fancy color diamonds.
Pink
Pink diamonds get their rosy color from plastic deformation of the crystal structure. Intense heat and pressure distorted the diamond’s carbon bonds while it formed in the earth. The more intense the pink, the higher the diamond’s value. Vivid purplish-pink and orangey-pink diamonds are especially prized.
Blue
Blue is one of the rarest diamond colors. These diamonds get their color from the element boron. Trace amounts of boron within the crystal structure absorb red, orange, yellow, and green light, transmitting only blue light. The stronger the blue color, the higher the price. Famous blue diamonds include the Hope Diamond.
Green
Natural green diamonds are very rate. Their color results from radiation exposure or hydrogen impurities. The Dresden Green is the largest known natural green diamond at 40 carats. Vivid emerald greens with no secondary hue are the most valued.
Red
Red diamonds are exceptionally rare, with very few natural specimens known to exist. Their red color comes from structural lattice defects. Often the color is not a pure red but tinted with purple or orange. The Moussaieff Red is the largest known red diamond at 5.11 carats.
Purple
Purple diamonds get their color from structural imperfections similar to pink diamonds. They range from plummy purples to rare vivid violets. The Royal Purple Heart Diamond exhibited at the Smithsonian is one of the few pure purple diamonds known.
Gray
Gray diamonds are caused by crystal lattice distortions. Desirable gray diamonds exhibit intense dark charcoal hues. Large gray diamonds are rare, like the 35-carat Asscher-cut Jubilee Diamond.
Black
Black diamonds are not truly black, but very dark shades of gray. These diamonds form through exposure to radiation or an abundance of crystal defects. Black diamonds are often heat treated to intensify their color saturation. Small black diamonds are readily available.
What are the rarest diamond colors?
The most exceptionally rare fancy color diamonds are red, purple, and pure green. Here is an overview of some of the rarest diamond colors:
Red
Red diamonds contain so many crystal irregularities that there are very few with pure enough structure to exhibit a strong red color. Only a handful of natural red diamonds over 5 carats exist. At 5.11 carats, the Moussaieff Red is one of the largest known natural red diamonds.
Purple
Pure purple diamonds with no secondary hue are exceptionally scarce. Even many famous purple diamonds, like the Royal Purple Heart, have hints of pink, blue, or gray secondary colors. An unmodified purple color is highly prized.
Vivid green
True green diamonds without any yellowish, brownish, or grayish modifiers are incredibly rare. Most natural green diamonds have secondary hues. The Dresden Green, the largest natural green diamond at 40 carats, has a slightly yellowish tint. An intense, pure green would be remarkably rare.
Blue
Blue is also exceptionally rare. Strongly saturated blues like the Hope Diamond’s vivid grayish-blue occur in a tiny fraction of all diamonds. Pure blue is one of the most coveted diamond colors.
Pink
Pure pink diamonds with no hints of purple, orange, or brown are very rare. Most pink diamonds fall into purplish-pink or orangey-pink secondary color categories. A true vivid pink without modifiers is exceptionally scarce.
How are diamond colors graded?
Gemologists use grading systems to evaluate and categorize fancy color diamonds. The systems evaluate the diamond’s primary hue, color intensity, and any secondary hues. Two common grading systems are:
GIA scale
The Gemological Institute of America (GIA) uses a nine-level grading scale based on hue, tone, and color saturation:
| Fancy Light | Fancy | Fancy Intense | Fancy Vivid | Fancy Dark | Fancy Deep | Fancy Pure |
| Fancy Lightish | Fancy Light | Fancy | Fancy Intense | Fancy Vivid |
Highest quality diamonds reach Fancy Vivid, Fancy Pure, or Fancy Intense rankings.
AGTA scale
The American Gem Trade Association (AGTA) categorizes colored diamonds as:
| Fancy | Fancy Intense | Fancy Vivid | Fancy Deep | Fancy Dark |
Again, Fancy Vivid denotes the most desirable, saturated colors. Both scales indicate primary and secondary hues, like “Fancy Intense yellowish green.”
How much do colored diamonds cost?
Colored diamonds are exponentially more valuable than colorless diamonds. The strength of the color saturation greatly impacts the price. Some average price ranges are:
| Diamond Color | Price per Carat |
| Yellow | $1,000 – $25,000 |
| Pink | $20,000 – $1,000,000+ |
| Blue | $200,000 – $1,000,000+ |
| Red | $1,000,000+ |
| Green | $15,000 – $4,000,000+ |
| Purple | $50,000 – $1,000,000+ |
As shown, intense reds, greens, and purples fetch the highest premiums. Even low-saturation fancy yellow diamonds cost more than colorless diamonds. The stronger the color, the higher the price.
Are colored diamonds treated or real?
Naturally occurring fancy color diamonds are extremely rare and account for a tiny fraction of the diamond supply. However, the majority of colored diamonds on the market have been artificially treated to enhance their color. Common diamond treatments include:
HPHT annealing
Applying intense heat and pressure can enhance a diamond’s natural inclusions to intensify yellows and pinks. This is known as high pressure high temperature (HPHT) annealing. Only reputable gem labs can detect these color enhancers.
Irradiation
Exposing a diamond to radiation bombards it with neutrons or electrons to produce color centers. Irradiation can create blue, green, and black diamonds. Irradiated diamonds must be disclosed as treated.
Coatings
Diamond coatings involve depositing a microscopically thin colored film on the surface to produce vibrant colors. However, coatings can wear off over time.
Dyeing
Diamonds may be dyed via chemical immersion or fracture filling to add color. This color is not stable and has poor longevity.
HPHT synthesis
It is possible to produce diamonds in a lab using high pressure and heat. Synthetic diamonds can be made in yellows, pinks, blues, and greens to mimic rare colors. These man-made diamonds are much more affordable.
How can you tell if a colored diamond is real?
Reputable gemological labs like GIA and AGS can authenticate natural fancy color diamonds. Here are some ways to tell if a colored diamond is real or treated:
Get laboratory certification
Have the diamond graded and certified by GIA or AGS. The lab report will state if the color is natural or modified. Beware of sellers offering colored diamonds without official grading reports.
Look closely at the color distribution
Treated diamonds often have concentrated, uneven color zoning. Naturally colored diamonds tend to have a more even color distribution.
Check for wear
Coated or dyed diamonds may show signs of color wearing off at facet edges and the girdle rim. Natural color will be stable across the entire surface.
Know the source
Reputable high-end jewelers will provide official certification of a diamond’s natural color. Generic or commercial retailers are more likely to sell treated diamonds.
Beware drastic discounts
Natural fancy colors have immense value. If a dealer offers colored diamonds well below typical price ranges, they are likely treated or synthetic.
Conclusion
Yes, natural fancy color diamonds occur in a rainbow of hues like yellow, pink, blue, green, red, and purple. These colors arise from chemical impurities and structural irregularities when the diamonds formed billions of years ago. Colored diamonds are exponentially rarer and more valuable than colorless diamonds. However, most colored diamonds today have been treated to enhance their color. Reputable grading reports, distribution of color, telltale wear signs, source, and pricing help determine if a colored diamond is natural or treated. In the end, it takes an expert eye to ensure the authenticity of these rare and priceless diamond treasures.
