Diamond Color Scale: Color Types and Coloration in Diamonds

While completely clear colorless diamonds are the most precious stones, fancy colored black, pink and blue diamonds, which are also very rare, are just as valuable. These different colors of diamonds are priced according to how rare their color is in nature. The internationally accepted GIA color chart is used to determine the colors of the engraved diamond stones. So, do you know which colors the diamond color scale contains?

Although colorless diamonds are traditionally considered the most precious stones, colored diamonds, which are among the jewelry of celebrities, have become very popular in recent years. We can list the colors of some diamonds found in nature as follows; Blue diamonds, pink diamonds, yellow diamonds, orange diamonds, green diamonds, champagne diamonds, gray diamonds, black diamonds, red diamonds, and purple diamonds. Although all these colors are very rare, they can be found in nature.

Diamond Color Types and Their Characteristics

Naturally colored diamonds are extremely rare. It is estimated that there is one colored diamond for every 10,000 colorless diamonds. This rarity explains in the first place why these extraordinary jewels have been expensive and exclusive to monarchs and royalty for centuries, and also why they are so little known to the public.

Colored diamonds, which are true miracles of nature, occur in colors such as yellow, orange, green, blue, purple, pink, black, brown, and very rarely red. In total, more than 300 colored diamonds have been listed and registered so far. Colored diamonds that are extremely rare are very small and are less than an average carat. This rarity is explained by a very complex geological formation process that makes each of these diamonds unique. It is therefore up to you to choose the diamond color of your engagement ring according to your preferences and budget.

The color of diamonds is due to the presence of chemical elements and the deformation of the crystal. Yellow, orange, and brown diamonds are formed when nitrogen atoms are present in their structure. Orange is the rarest color. There may be several reasons for the formation of blue-colored diamonds. The most common reason for the formation of blue diamonds is the presence of boron in its content. The more intense the presence of boron, the more pronounced the blue color will be.

Colors such as pink, purple, and brown occur as a result of the deformation of the crystal structure. For example, the purple color occurs as a result of the displacement of the hydrogen atoms in the diamond. Green-colored diamonds are relatively complex and long in terms of formation processes. Diamonds are formed by exposure to gamma rays deep within the Earth for periods of up to several million years. This event causes the atoms to be displaced during the formation process of the diamond.

  • Blue Diamonds

One of the most impressive stones is the blue diamond. In the international classification, this color is called fancy blue. The extremely rare blue diamond has phosphorescence, meaning it glows under ultraviolet light. The blue diamond is a sign of elegance and high status. It is sold at prestigious auctions all over the world. A blue diamond gets its color from the introduction of boron atoms into the chemical structure of the diamond during its formation. The presence of boron atoms gives diamonds reflective properties. The first blue diamonds were discovered in the mid-1600s. Blue diamonds are so rare in nature that only one of every 10,000 diamonds is blue.

The color of blue diamonds is quite diverse and can have a wide color intensity, from the extremely rare dark blue to a light blue hue. Such diamonds are called “ice blue”. The brightness and saturation of the color depend on the number of boron atoms in the chemical structure of the diamond. If the diamond contains other chemical elements in addition to boron atoms, it causes a different shade to appear in a blue diamond. For example, the nitrogen in it can give a blue diamond a yellowish hue. Blue diamonds with bright, intense, and pure colors are extremely rare in nature.

  • Pink Diamonds

The pink diamond has long been considered the rarest of colored diamonds. There is only one pink diamond among 100 thousand diamonds found in nature. There are 20 shades of pink diamonds with different color saturation. Pink diamonds are mined only a few times in the world. Currently, the main source of the pink diamond is a mine in northwest Australia. Pink diamonds are also mined in Africa and Brazil.

Pink diamonds are very rare in nature. Therefore, the price of pink diamonds, like other colored diamonds, is not fixed. A diamond is graded according to its carat weight, cut quality, clarity, and color of the diamond. If the price of a stone for white diamond increases depending on its transparency, for colored diamonds such as pink, the more intense the color of the stone, the higher the price of the diamond. In addition, color integrity and color saturation are very important for colored diamonds. For example, if a pink diamond has a yellowish color, the price of the stone will drop significantly.

Pink diamonds can only be bought at an auction or on the diamond exchange. Pink diamonds start at $80,000 per carat. The price for large pink diamonds can be up to a million dollars per carat. One of the world’s rarest pink diamonds has been auctioned for a record $46 million.

  • Yellow Diamonds

Due to their rarity and high price, yellow diamonds are not found in jewelers, they are only sold at auctions. The price of a natural yellow diamond is very high and can even reach 1 million dollars per carat. The price of a yellow diamond depends on its cut and clarity. The largest known yellow diamond (weighing 110.03 carats) was sold for $55 million. The first 287-carat golden yellow diamond was found in South Africa in 1887.

Yellow diamonds are mined from Australia, Botswana, Tanzania, and Russia. Yellow diamonds are graded based on three criteria: size, clarity, and color. The most important yellow diamond to date is the 545.67-carat golden jubilee diamond found at Premier mines in South Africa in 1985.

  • Black Diamonds

Black diamonds are thought to have been brought to earth by meteorites. Also, scientists estimate that black diamonds are four billion years older than their counterparts. In laboratory studies, it has been shown that black diamonds contain hydrogen, which is found in space at a high rate. The first specimens were accidentally found in Brazil and Central Africa. There are two types of black diamonds in nature: carbonado and pike.

Carbonado – A stone composed of irregularly shaped crystal grains with pores on it. The crystal absorbs light instead of reflecting it. It is not used much in the jewelry industry, as it can crack when cut and is impossible to polish. It is generally used as a raw material in men’s cufflinks and in the manufacture of technical devices in the industry.
Pike – It is a black crystal with a transparent structure. Dark green, brown, gray specimens are also considered black.

  • Green Diamonds

The green diamond is very rare in nature and is the second rarest diamond after the red diamond. Green diamond has different shades: light green, intense green, bright green. The brighter and more intense the color, the more expensive the diamond. True green diamonds are extremely rare. The main deposits of green diamonds are located in the southern part of Africa. In addition, green diamonds are mined in Brazil, Australia, Ghana, Congo, and Siberia.

Diamond takes on a green color due to exposure to natural radiation during its formation. This process can take millions of years. The depth and distribution of green in the stone depend on the type of radiation. Alpha radiation produces surface coloring in the stone in the form of green spots or a thin green film, which is often lost during diamond machining. Beta and gamma rays penetrate deep into the diamond and give the stone a steady green color. Naturally formed green diamonds in this way are much less expensive and more expensive.

  • Red Diamonds

One of the rarest and most exquisite gemstones is the red diamond. It is quite rare in nature. Therefore, the red diamond is a sign of luxury, taste, and the special status of its owner. The price of a red diamond is really high. It is necessary to see this stone not only as a gift but also as a safe investment tool. The price of a red diamond is increasing significantly every year. There are only 30 red diamonds in the world. A collector’s staple, this stone was sold at a private auction last year for a record $1.6 million per carat.

Among the colored diamonds, the red diamond is considered the most mysterious stone because no one knows what causes the color in the stone. Most of the red diamonds found to date have been mined in Australia, and very few red diamonds have been found in other parts of the world, such as Brazil and South Africa.

Diamond Color in Jewelry

When diamond jewelry is to be purchased, whiter (transparent) color stones are generally preferred. The color of the diamond is evaluated in five general categories on a scale from D to Z. These; extra white (colorless), white (nearly colorless – almost colorless), weak yellow (faint yellow), very light yellow, and light yellow. Here, you will see the dominant color in the diamond while determining the color scale. The predominant color in transparent diamonds is the yellow color resulting from the trace of the nitrogen element. As the nitrogen content in the diamond decreases, its value and whiteness increase.

Generally, when comparing the color between two diamonds, the diamonds should differ from each other by at least two degrees so that the difference can be understood. The following diamond color ranking of diamond colors table shows us that it is almost impossible to see a color difference between two consecutive color grades. Although the diamond creates splendor with its brilliance and beauty when viewed from the top angle, some color changes can be seen when viewed from the side angle.

The most common misconception about diamond color grading is the structure of the grading. The diamond color scale, which is generally thought to start with the letter A, starts with D. So why does this rating start with the color D? Before the grading system set by the GIA (American Institute of Gemology) was widely accepted, different diamond traders specified the best diamond color with “A”, “AA” or other different designations.

As might be expected, in such an uncertain environment a great deal of inconsistency arose and the terms used to describe a diamond inevitably led to great confusion. The main reason why the GIA color grading system, which is widely used today, started with D was to ensure that it was not confused with the inconsistent grading systems used in the market at that time.

Coloration of Diamonds

The most common color in diamonds is brown. Brown diamonds are found in the rings of the Romans. It is generally used in industry, where it is not in demand as jewelry. Today, however, this view has changed drastically with the discovery of large quantities of brown diamonds from the Argyle mine in Australia. Light brown ones are sold under the name “champagne”, and dark ones are sold under the name “cognac”.

Brown coloration in diamonds is due to various reasons. Brown thin parallel lamellae are seen in some diamonds. The thickness of these lamellae is a few hundredths of an mm. Although their origin is unknown, they are thought to have arisen from deformation in the structure. The brown coloration is seen less frequently due to the color centers.

For example, defects with H and the presence of isolated nitrogen atoms and “amber” color centers sometimes produce brown coloration. Recently, greenish-brown diamonds have been sought under the name “olive”. Sometimes stones turn brown when exposed to radiation, which is not the desired result.

The second most common color in diamonds is yellow. Yellow diamonds have been found in the Cape region of South Africa. Today, yellow diamonds are called “cape stones”, although they are also found in other regions. The coloration comes from N3 color centers formed by three nitrogen atoms, isolated nitrogen groups absorb violet and blue light, resulting in yellow color. Dark yellow colors are called “canaries”. To darken the color of a light yellow diamond, the diamond is first excited by radiation and then heated. Thus, a more valuable dark yellow color can be obtained in the market.

The most interesting colors seen in diamonds are pink, red, and purple. The 185-carat pink diamond “Darya-I Nur” was among the Mongol rulers who ruled in India in the 17th century. It is now regularly mined in the Argyle mine in northern Australia, although traces are found in Brazil, Indonesia, and Tanzania.

The causes of coloration in red, pink, and purple diamonds have not been fully elucidated. Pink parallel lamellae were seen in some. Coloration occurs in a significant part of it due to a wide absorption band with a center of 550 nm. This absorption is thought to be due to a deformation in the diamond structure. Diamonds from the Golconda region in India are always pale pink. Their coloration is due to their color centers, which contain very little N. For artificial coloring, diamonds containing isolated nitrogen atoms are irradiated, and then, by controlled heating, pink color is obtained.

The most famous blue diamond is the 45-carat “Hope” diamond of Indian origin. It is currently in the Smithsonian Museum in the USA. Blue diamonds have also been found in Brazil and Indonesia at the Premier mine in South Africa. The blue color is caused by boron in the crystal structure. As the boron amount increases, the color becomes darker. Such diamonds are also semiconductors. Apart from this, color centers are formed in diamonds that have been naturally exposed to radiation and the diamond acquires a blue color.

Such diamonds are not conductive. Blue diamonds found in the Australian Argyle mine are rich in hydrogen. The coloration is thought to be caused by the color centers formed by the hydrogen. In laboratories, diamonds that do not contain boron (light brown diamonds) acquire a blue color with the effect of radiation. The colors of such diamonds resemble aquamarine blue.

Green diamonds are very rare. In many, the green color is limited to a very thin superficial layer, and when it is exposed, this layer and its color disappear. The most famous green diamond is the 41-carat Dresden Green. This diamond was thought to have come from India. But now it is understood that he is of Brazilian origin. Although green diamonds are rare, the reasons for their coloration are varied. These are radiation effect, fluorescence effect, H-related defects in the structure, and other unknown defects.

It is very difficult to separate the green diamond colored with radiation from the real ones, but with the developing technology, the color distribution can be controlled with spectrometers in a range from ultraviolet to infrared. Natural green diamonds are valued at very high prices. Most green diamonds in the jewelry market are considered to have been traded.

Saffron-colored diamonds are the rarest species. Although the reason is not known exactly, it is thought to be related to the N it contains. The coloration of the brownish-orange ones is related to the H3 and sometimes H4 color centers. Another recently identified color is purple. It was found in the Argyle mine in Australia. All of them are rich in hydrogen, no purple diamonds obtained by processing have been found.

There are also black, gray, and white-colored diamonds. Black diamond has also attracted attention in ancient times. Like the 67.5-carat Black Orlov that once belonged to Nadia Vygin-Orlov. In the 1990s, black diamonds came into fashion. The coloration is due to very small black scaly inclusions, which were generally thought to be graphite. So much so that graphite inclusions in some stones create electrical conductivity. Because of the inclusions, such diamonds are very difficult to polish and seldom have gem quality. Most black diamonds are colored by exposure of poor quality diamonds to neutrons.

White diamonds show “opalescence” and their milky white color is caused by the scattering of light from the inclusions found in such stones. It is not known what these inclusions are, but white diamonds contain nitrogen-rich boron particles and plaques.

Gray diamonds are rich in hydrogen. Coloration is due to hydrogen-related defects. In such diamonds, the absorption is of equal intensity for all wavelengths, resulting in gray color. Nowadays, colored diamonds are more popular and sought after than ever, especially natural blue, green, pink, red, and purple colored diamonds are very rare occurrences and very valuable. They always fascinate people and arouse the interest of scientists. The reasons for the coloration, on the other hand, still remain a mystery to some extent, despite many studies.

Fluorescence, Phosphorescence and Artificial Coloring in Diamonds

Crystals can also absorb radiation of wavelengths other than visible light. Some of the energy gained comes out in the form of visible light. In diamonds, fluorescence and phosphorescence are sometimes seen along with coloration. These are called “chartreuse” diamonds, “green transmitters” or “green emitters”. Some yellow diamonds show strong green radiation. Here, the H3 assemblage in the structure cools the blue. The intensity of the green component of the color changes according to the composition of the stimulating light. Accordingly, it is brighter in blue-rich daylight. strong green radiation is seen.

Since naturally colored diamonds are very rare and precious, the artificial coloring of colorless diamonds is attempted. The type of radiation used and the properties of the diamond play an important role here. When diamonds exposed to ultraviolet, gamma, or alpha rays are heated, a yellow, orange or pink color can be obtained. The pink color occurs depending on the properties of the sample being studied, the irradiation process, and the heating conditions. Some ions of diamond that have been exposed to radiation are thought to lose an electron from their outer shell.

This energy-absorbing electron moves to the conduction band. If the lattice is perfect, when the excitation ends, this electron returns to its original place. If the lattice is defective, the local energy level in which the electron moves will occur, and because the energy distribution in the crystal changes, color centers that absorb light energy will occur. Thus, the coloring continues even when the stimulating radiation stops.

Best Colored Diamonds That You Can Buy Online

Savaş Ateş

My wife has a huge interest in diamonds. After she asked me a lot of questions about it, I found myself in diamonds. I made a lot of research on it. I read books. I visited manufacturers. I visited the stores. I have made good friends in that field. I want to share my experiences with you.

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