Brown Diamond Value, Price, and Jewelry Information

Brown Diamond Value

Rebranding efforts have certainly caused the demand for brown diamonds to increase and have created a whole new space in the marketplace that previously wasn’t there. Gems that historically were worthless in the jewelry market suddenly became valued commodities. Thankfully, as there are so many brown gems to be had, they remain one of the most affordable of the fancy-colored diamond varieties.

Interestingly, brown diamonds which express a secondary color can also hold quite a bit of value. As will be described below, brown diamonds may have a secondary color of pink, orange, or yellow. These are considered by many to be superior to, thus more valuable, than pure brown gems.

Color Grading Brown Diamonds with the GIA System

The way that fancy-colored brown diamonds are graded involves the marriage of two different systems which are sometimes used concurrently. The first of these systems in the GIA’s normal color range scale, alternatively known as the “D-to-Z” range. Diamonds with a perfect grade “D” are colorless stones that have absolutely no trace amount of any color and they are exceptionally rare. With each step down the alphabet, gems show slightly more color – specifically yellow, brown, or gray hues. These three hues are separate from all other body colors as even the slightest amount of any other color such as pink or green are automatically considered fancy-colored diamonds.

When to Use the GIA Colorless Diamond Color Grading System

Diamonds with minor brown expression are graded according to the D-to-Z scale normally until the letter grade “K.” Once a diamond has enough brown to be classified a “K” stone, the second system, the GIA’s 9-level Colored Diamond Color Grading System, is also implemented. The nine grades of this system listed from least to most color expression are as follows: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Dark, Fancy Deep, and Fancy Vivid.

When brown diamonds have a letter grade of “K” through “M,” the certificate will also include the first of the Colored Diamond grades – “Faint Brown” to the official color declaration. So, for example, a grading report will list the color grade as “L, Faint Brown.” After “M,” grades “N” though “Q-R” are considered Very Light Brown. An example of this type of diamond would be “P, Very Light Brown.” The remainder of the scores, “S-T” through “Y-Z” are paired with the color grade of “Light Brown.”

When to Use the GIA Colored Diamond Grading System

Once a diamond has enough color to be graded below “Z,” the Colored Diamond Color Grading System is used on its own. The first colored diamond grading level used independent of the normal color scale is Fancy Light Brown.

The Argyle Brown Diamond Color Grading System

Beyond the GIA’s system of color grading, Argyle developed their own classification scale to grade their brown diamonds. This scale has seven levels called C1-C7 where C1 has a light brown color and each following score shows more brown. Specifically, gems graded C1 or C2 have a light brown color, C3 and C4 are a medium brown, C5 and C6 are dark brown, and finally, C7 diamonds are called “cognac.”

Does Brown Diamond Make a Good Jewelry Stone?

There are no additional durability concerns with brown diamonds. They have the same resilience as colorless diamonds. This means that normal exposure to light, heat, and everyday chemicals won't harm gems and you can clean them using any traditional jewelry cleaning technique including ultrasonic machines, steamers, and jewelry cleaning solutions. 

As with all diamonds, there is a risk that they will chip if they are impacted with enough force. If you plan to wear your brown diamond in high-risk jewelry (such as rings that you wear often), consider settings that protect corners, edges, and points.

Fortunately for consumers, lovely brown diamond jewelry is commonplace, but their price-per-carat costs remain among the lowest of all the fancy colored diamonds. This makes fancy brown diamonds one of the most accessible diamond colors on the market.

Even with the increase in demand for brown diamonds, it is still relatively unusual for pure brown gems to be sold for use in jewelry. More often, the color of brown gems needs to be paired with other hues like red, pink, orange, or yellow for them to survive the culling process. Many gems are treated to induce or enhance a secondary hue.

Matching Brown Diamonds

Thanks to their abundance, finding brown diamonds with similar carat weights and color is easy. As such, you will often see jewelry set with multiple brown gems that are perfectly matched across all of the Four Cs.

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The History of Brown Diamond

Archeological research has shown that fancy brown-hued diamonds were used by the ancient Romans in their jewelry as early as the second century CE. The surviving rings are the earliest example of mankind using any fancy-colored diamond. 

The Argyle Brown Diamond Marketing Campaign

Fast forward to the modern era, the world-renowned Argyle Mine commenced operations in 1983 and it quickly became apparent that they faced a dilemma. While they were producing 90% of the world's highly-valued pink diamonds and, at times, were unearthing more carats of diamonds than any other mine on Earth, lots and lots of their gems were brown. In fact, about 72% of their total gem yield showed some degree of brown color.

At that time, fancy brown diamonds were considered unusable by jewelers due to lack of demand by consumers. Instead, such gems would be destined for industrial purposes which included being used as abrasives, drill coatings, and set into computer chips. However, such gems didn't sell for the same price as gem-quality stones. This hampered profits, so, what was Argyle to do?

The ultimate decision was masterful: they started a marketing campaign. Fancy brown gems were rebranded using appealing names like "champagne," "chocolate," and "cognac" and demand quickly soared. Some of the biggest names in the jewelry business adopted this new naming practice and began utilizing brown stones in their fine jewelry collections. Soon, brown diamonds were being used in jewelry at all pricing tiers. Now, there are even companies that specialize in fancy brown diamonds.

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Brown Diamond Color

The color of some brown gems can be equally distributed throughout the crystal. However, the color expression of some brown diamonds may be zoned, meaning that some regions of the crystal are darker or more saturated than others. This can be true of their pink cousins as well.

The skill of a diamond cutter can greatly impact the apparent color distribution in a brown gem. If the cutter orients the gem properly, they can minimize color zoning and mask any visible graining pattern (more on that to come). Obviously, they don't have control over the color expression of a gem, but a good cutter can bring out the best in a diamond.

What Causes Brown Diamond Color?

There are a few causes of brown color in diamonds, but the most common are carbon vacancy clusters and deformation lamellae formed as a result of natural plastic deformation. To understand these structures and why they are formed, we need to first explore the atomic structure and composition of pure, colorless diamonds.

Diamond Crystal Structure

The ideal atomic structure of diamonds is characterized by carbon atoms aligned in a perfect cubic formation. These gems are colorless, and it is the incredible symmetry of this structure that makes diamonds the hardest naturally occurring mineral on Earth. However, the very mountain-building activity that brings diamonds to the surface also exposes gems to extreme conditions that can force their homogenous atomic arrangement out of shape. This process is called natural plastic deformation and it creates layers of deformation lamellae and individual sites of carbon vacancies that alter the color of diamonds from colorless to brown. Specifically, temperatures above 900^o C are required to trigger this deformation process.

The Argyle Mine was located on an ancient site of continental interaction which fostered extreme heat and pressure, which is why it produced so many brown diamonds. The same process which causes a brown coloration also makes pink, red, and purple hues which is why Argyle also housed so many of those gems as well. A small amount of pressure will make a pink or red diamond while more results in brown. Let's look at this process more closely.

Deformation Lamellae

When carbon atoms are forced to slip, they do so along the octahedral plane which is an angle of inherent weakness in the formation of carbon atoms. This process usually creates many parallel planes of slippage inside the gem, rather than just one. These internal stripes are called "colored deformation lamellae" or, alternatively, "graining," and the more the diamond has, the darker its color expression.

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Whatever you choose to call them, these bands change how light behaves in the crystal, creating and concentrating brown color inside of themselves. Collectively, the planes where graining has been forced to appear are called "color centers" because most, if not all, of the color of brown gems are contained in them while the body of the crystal remains mostly colorless.

Carbon Vacancy Clusters

Once the individual carbon atoms are pushed out of place, the regular cubic structure of the crystal lattice does not bounce back into alignment. Rather, some individual positions where carbon atoms should be remain vacant. Like the graining layers, these vacancies often occur in clusters, rather than single isolated sites. One recent study that examined the mechanisms behind a brown expression stated that there are usually between 40-60 irregularities per location. Like the graining, vacancy centers redirect light to initiate a brown color expression.

Diamonds made purely of carbon are rare because the growing environment inside the Earth usually contains other elements that are incorporated into the diamond as it grows. Nitrogen is by far the most common chemical impurity seen in diamonds and they can take the place of carbon atoms inside the crystal lattice. Since carbon and nitrogen atoms are different sizes, nitrogen substitutions slightly distort and weaken the crystal structure. It is due to this weakening that the vacancies caused by sheer stress described above can occur alongside individual nitrogen substitutions.

Diamond Types

As most diamonds have nitrogen in their lattice, gemologists divide gems into two categories: stones with nitrogen and stones that lack nitrogen. Diamonds with nitrogen are considered Type I stones and they make up the vast majority of mined gems. There are two subcategories of nitrogen-rich Type I stones that describe how the element is distributed inside the crystal. Type Ia gems have nitrogen atoms that are bound to each other. When nitrogen atoms are paired up, they create what is called an A-center. A carbon vacancy surrounded by four nitrogen atoms is a B-center. Most diamonds are hybrids featuring both A and B centers, and diamonds are classified as Type IaA or Type IaB depending on which type is more abundant. It is interesting that stones with an unmodified brown hue tend to be Type IaB rather than Type IaA.

Diamonds with isolated nitrogen atoms at classified as Type Ib but these typically are not brown. Type II diamonds lack nitrogen and are quite rare, but, when they lack boron and are classified as Type IIa they can express a brown color.

Why Do Pink and Brown Colors Often Occur Together?

As pink diamonds are colored due to similar color centers that cause brown, gems often show both hues at the same time. This means that there are plenty of lovely pinkish-brown or brownish-pink gems out there. Besides pink, the color of brown diamonds may be modified by purple, orange, or yellow.

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In addition to graining and carbon vacancies, some rare brown diamonds originate in super-deep conditions which are defined as deeper than 250 km. Many of these stones also have at least some pink. Scientists know that such stones formed so deep within the mantle due to inclusions contained within the gem which only occur in the lower mantle. These stones are so unusual that a specific geographic site has yet to be identified. A few gems are confirmed to be of African origin, but the provenance of many remains unverified.

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Some Brown Diamonds Aren't Brown

Finally, it is also possible that brown diamonds aren't actually brown. They might be yellow or orange diamonds whose saturation is so low that the hue is almost completely masked by its tone.

Brown Diamond Trade Names

Brown diamonds owe their current worth and desirability in the jewelry market specifically to the use of trade names. It was a truly brilliant marketing strategy by Argyle to employ descriptions using romantic and luxurious words like "chocolate" and "cognac" to increase the appeal of brown diamonds to the general public. Dealers continue to embrace this technique and you will still see many non-traditional words used to describe brown gems. But, remember that only the two GIA grading scales, the D-to-Z scale and Colored Diamond Color Grading System, are globally regulated. Whenever purchasing a fancy-colored brown diamond, it is always best to see the actual gem rather than trusting a description.

Identifying Brown Diamonds

Standard Diamond Characteristics

While issues like fluorescence change with the various fancy colors that diamonds can exhibit, some measurements are universal.

• Using a standard refractometer, diamonds will register as over the limit (OTL). 
• Their dispersion which causes the beautiful multicolored fiery flashes that diamonds are known for is 0.044. 
• They will not show birefringence (also known as doubling) and are not pleochroic. 
• Lastly, their specific gravity (SG) is 3.52 (+/- 0.10).

Absorption Spectrum

The visible absorption spectrum for brown diamonds shows high absorption of the shorter wavelengths which removes violet and blue, and a gradually increasing absorption to the lower wavelengths to allow brown to shine. Specifically, the spectra of brown diamonds usually show an absorption band at 550 nm which is associated with plastic deformation. This band may be present in stones that show both pink and brown, however, unmodified brown gems only show a tiny absorption band there.

Some rare brown diamonds paired with an expression of red may show the 550 nm band paired with another line at 480 nm. These bands remove both blue and orange hues, resulting in brown-red stones.

Fluorescence

If a brown diamond fluoresces, it likely will exhibit a blue color which is notably stronger under longwave UV than shortwave UV.

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Clarity Features

As brown diamonds are found alongside colorless diamonds, you are likely to encounter the same type of inclusions. These include dark graphite, which is carbon that failed to convert to diamond, as well as trapped zircon, rutile, or diopside crystals. These inclusions may be clustered together, spread around the diamond crystal, or occur in isolation. Due to the abundance of brown stones, the clarity grade greatly affects the value of individual gems. If you find a gem that has large, eye-visible black spots, regardless of its size or color, that diamond won't be worth much.

While you can expect to see the graining pattern relatively easily using magnification, it won't appear on the plot of the diamond in its grading report. You will only see a note in the comments section confirming its presence.

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Are There Synthetic Brown Diamonds?

As brown diamonds are priced modestly when compared to other fancy colors like pink and blue, it is somewhat difficult to find synthetic gems because labs would rather grow other, more profitable, colors. In fact, a search of the webpages of companies that sell lab-grown diamonds such as James Allen and Brian Gavin Diamonds will show a wide selection of natural brown diamonds but, as of the time of publication, no lab-created stones.

You will find lab-grown brown diamonds on the market that were created using either the CVD (chemical vapor deposition) method or the HPHT (high pressure/high temperature). The CVD process is characterized by aerosolizing the necessary chemical components and allowing the diamond to crystalize around a seed diamond while HPHT mimics the natural growing environment inside the Earth by heating and squeezing carbon.

Diamonds created by CVD may be subjected to secondary treatments to enhance their color. For example, Brown Orange CVD gems have been found that were both irradiated and annealed. Some have speculated that such treated synthetic brown diamonds were meant to become pink or red but the process failed because the nitrogen atoms were not aligned properly to achieve that color.

Brown Diamond Enhancements

Because brown diamonds have such low price-per-carat values when compared to the other fancy colored stones and even colorless diamonds, treatments that are applied are usually done to reduce or remove the brown, rather than enhance it.

One of the most common treatments that can be used on brown Type 1aB and Type IIa gems is a high pressure/high temperature (HPHT) treatment (this is different from the HPHT growth process) that increases the 550 nm absorption band. In doing so, the expression of brown is decreased while pink is enhanced. Similarly, HPHT treatment paired with annealing (a tightly controlled process of heating and cooling) dissociates the vacancy centers to decrease brown expression.

You may also come across brown gems that have been irradiated to induce a red modifier.

Where are Brown Diamonds Found?

About three-quarters of the diamonds from the Argyle Mine in Australia were brown to some extent. That particular mine ceased operations in 2020 and the environmental reclamation process is well underway. Today, brown diamonds are found alongside colorless gems in most mines all around the world. This includes mines in South Africa, Borneo, Siberia, Brazil, Angola, and the Congo to name just a few.

Famous Brown Diamonds

The Golden Jubilee Diamond

Some say that the Gold Jubilee Diamond is the most famous brown diamond in the world despite only having recently been found in 1985. Ten years after its discovery, Pope John Paul II himself blessed this gem. It also has the distinction of being the world's largest faceted diamond weighing in at 545.67 cts. The gem was presented to the King of Thailand during the jubilee celebration in honor of his fifty years on the throne which is where it got its name. Like many brown diamonds, the brown hue of the Golden Jubilee is paired with another color. In this case, an equally intense yellow hue with an official color grade of Fancy Yellow Brown. The rough crystal contained several internal fractures, it took two years to facet into a modified version of cushion cut called Fire Rose Cushion Cut.

The Star of the South

Minas Gerais in Brazil may be known for its emeralds, but it also contains a wealth of other stunning gemstones, diamonds included. The Star of the South is a 128.48 ct. diamond that was found in 1853. Graded by the GIA to be a Fancy Light pinkish brown, this gem was the first diamond of Brazilian origin to gain international acclaim. As such, its early history has been well documented. The story goes that a slave woman working for a mine found this stone and dutifully turned it into the mine's owners. As a reward, she was granted freedom and a lifelong pension. A study published in 2002 that examined this gem said that brown lamellar bands were observed inside the crystal.

The Golden Maharaja

No one knows why this Fancy Dark Orange Brown diamond is named The Golden Maharaja, but it is thought that it was mined in Africa. The debut of this gem was the 1937 World Fair in Paris. The gem was loaned to the American Museum of Natural History from 1975-1990. After that, the diamond sold at auction twice, most recently in 2006 fetching a price of almost 1.4 million dollars.

The Great Chrysanthemum

This is an unusual gem in that its graded color is a true brown not modified by any secondary hue. Cut into a 104.16 ct. pear shape, this gem was unearthed in South Africa in 1963 and is currently owned by Garrards of London.

Brown Diamond Sizes

As the list of famous brown diamonds shows, we know that brown diamonds can be absolutely massive in size. There are also tons of tiny melee gems to be had. Basically, if you can dream up the perfect brown diamond, chances are that you can find one, two, or many, in the real world.

How to Care for Your Brown Diamond Jewelry

Fortunately keeping your brown diamond jewelry looking its best is easy as the durability of individual gems is so high. As always, if your brown diamonds have been treated, always alert your jeweler before they do any work including resetting or resizing. See our gemstone jewelry cleaning guide for more recommendations.