Black Diamond Value, Price, and Jewelry Information
Black is a color that can say a lot. Wearing black diamond jewelry communicates a sense of unique strength and confidence while simultaneously being elegant and versatile. No matter how you wear your black diamonds, you can be sure that others will notice the unconventional choice. They have become an especially popular choice for men's jewelry. Let's learn about this bold gem.
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Black is a color that can say a lot. Wearing black diamond jewelry communicates a sense of unique strength and confidence while simultaneously being elegant and versatile. No matter how you wear your black diamonds, you can be sure that others will notice the unconventional choice. They have become an especially popular choice for men’s jewelry. Let’s learn about this bold gem.
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Black Diamond Value
Fortunately, black diamonds are a very affordable variety of fancy colored diamond. There are three primary reasons for this:
- Black diamonds are relatively common when compared to other fancy colored diamonds like green or red.
- Many low-quality diamonds (particularly gray diamonds) with lots of internal fractures are turned black with treatments, further adding to the available inventory.
- Demand remains relatively low. As such, per-carat prices remain very affordable even for larger gems.
Why are Black Diamonds Considered Achromatic?
In many ways, black diamonds are graded differently than other fancy colored diamonds. Issues arise from the gemological definition of “color.” Basically, the concept of color is broken down into three constituent parts: hue, tone, and saturation. Hue is what we most often think of when someone mentions color. Some officially recognized hues include “blue” and “purple.” Tone describes how dark the stone’s hue appears. Saturation defines the hue’s intensity.
Black is not considered a hue and has no range of saturation. Rather, it is simply tone at its most extreme expression. Thus, you may hear black diamonds, along with white and gray gems, referred to as “achromatic,” meaning “without color.”
Black Diamond Grading
Most fancy colored diamonds are graded using the GIA’s nine-step Colored Diamond Color Grading System. However, because black diamonds are either black or not, they are simply graded as “Fancy Black.” The only other fancy colored diamonds graded only using the term “Fancy” are red and white diamonds.
Additionally, as most black diamonds owe their color to a massive number of solid inclusions and are mostly opaque, a clarity grade isn’t applicable.
For these reasons, the GIA will not issue a standard grading report for black diamonds. Instead, they will only certify these stones with their Colored Diamond Identification and Origin Report.
Does Black Diamond Make a Good Jewelry Stone?
Black diamonds often owe their color to dense concentrations of large dark inclusions. Because of this, their structural integrity is notably weakened. This makes black diamonds a challenge for cutters to facet and polish. Whole chunks of a stone can simply crumble away with a single cutting error.
Even after shaping, black diamonds remain especially vulnerable to chipping or even breaking if impacted. Wear any rings and bracelets with black diamonds with special care. Ideally, choose a protective setting that shields all edges and points of the diamond.
Matching Black Diamonds
You can match black diamonds relatively easily because you only need to consider two of the Four Cs: cut and carat. (By definition, all black diamonds match color and clarity). Natural black diamonds are relatively plentiful, and many of the stones on the market have been treated to maximize their black color. This means jewelers have a lot of inventory available.
The History of Black Diamond
Black diamonds were seriously underappreciated until the late 1990s. Before this time, there was virtually no consumer demand for Fancy Blacks, regardless of their size or shape. Most of these stones were set aside for industrial use.
Nevertheless, a few historical records mention some significant black diamonds. An early description comes from the 1928 book Diamond: A Descriptive Treatise. It offered a less than flattering comparison of this diamond's appearance to ordinary black wax.
While black diamonds do pose challenges to cutters, no one can deny that finished stones look stunning. Not surprisingly, their popularity spiked soon after designers started incorporating these black stones in their designs. Celebrities fueled this trend by sporting edgy engagement rings featuring black diamonds, both in real life and on screen.
What are Carbonados?
When researching or shopping for black diamonds, you might encounter references to carbonados or carbonado diamonds. Carbonado diamonds differ from other diamonds because they are aggregate stones rather than single-crystal gems. First uncovered in Brazil in 1841 and found only in Brazil and the Central African Republic, carbonado diamonds consist of many individual black diamond crystals, pieces of unconverted graphite, other forms of carbon, and large amounts of impurities cemented together. While these two nations are currently separated by an ocean, they were joined many millions of years ago. This means that all carbonado diamonds originated from a single ancient source split apart by plate tectonics.
Carbonado is the Portuguese word for "burnt" or "carbonized." It describes the physical appearance of most of these stones very well. However, carbonados can also have dark purple, pink, red, or green colors. These stones can reach famously massive carat weights and have glassy but visibly pitted surfaces.
Are Carbonados Black Diamonds?
Quite a few people use the terms "black diamond" and "carbonado" interchangeably. However, this is not correct. Black diamonds are single-crystal diamonds colored by inclusions, while carbonados are polycrystalline diamonds made from many tiny pieces glued together.
How do Carbonados and Black Diamonds Differ?
Black diamonds and carbonado diamonds have drastic differences in durability. One might assume a polycrystalline aggregate like a carbonado would be less durable than a single crystal stone. As it turns out, carbonado diamonds are significantly tougher than their single-crystal black diamond counterparts. They are far less likely to crack when impacted or subjected to high pressures. In fact, some carbonados are so strong that only lasers can effectively cut them. Many abrasives and industrial drill bits contain carbonados, due to this superior durability.
As rough stones, black diamonds and carbonados look very different. Black diamonds, like most conventional, single-crystal diamonds, grow smoothly. The best examples have an octahedral shape with a mostly smooth skin. Aside from their gargantuan size and pitted surfaces, carbonados usually form in cubic shapes.
Today, you can find both black diamonds and carbonados in jewelry, from affordable pieces to high-fashion creations.
Black Diamond Color
Most black diamonds get their color from a multitude of dark inclusions. This makes the stones opaque rather than transparent. (Most diamonds, both white and and fancy, are transparent). Since the inclusions make the stone appear black, the actual body color of black diamonds doesn't greatly affect their color expression. In fact, the diamond itself may be nearly colorless, brown, or even very dark green. You might observe this firsthand if you look at a black diamond under magnification using plenty of reflected light.
Black diamonds with beautiful, even color usually hold the most value. However, black diamond color isn't always evenly distributed because those inclusions aren't always spread out uniformly. Furthermore, the inclusions can also have a range of colors. This means you may encounter stones with a blotchy appearance. If the diamond has relatively few dark inclusions and you can observe a light body color without magnification, it's referred to as a "salt-and-pepper" stone.
Black Diamond Luster
If well-polished, black diamonds can have a very high luster and appear almost metallic under reflected light. Look for this when making a purchase. On the other hand, many small pits on the surface of the diamond indicate it contains lots of large inclusions and may be prone to break. A high luster indicates the stone was strong enough to withstand the polishing process and will likely hold up better over time.
What Causes Black Diamond Color?
Due to the lack of interest in black diamonds, research into the causes of their color has only occurred recently. Scientists have noted that the majority of black diamonds are colored by inclusions, while the color of the actual crystal can remain clear. Whether large or minuscule, inclusions make the diamond opaque. Let's take a look at a pure diamond crystal to understand how inclusions are distributed inside stones.
Diamond Crystal Structure
The pure diamond crystal has a basic form: individual carbon atoms arrange themselves into a very stable cubic formation as the result of the high temperature and intense pressure exerted on them inside the Earth's mantle. This atomic structure is so symmetrical and tight it makes the surface of gems practically impossible to scratch. Diamonds won't degrade over time. (You don't have to worry that someday you'll open your jewelry box and find soft hunks of graphite carbon have replaced your sparkling diamonds). Furthermore, because of diamond's atomic uniformity, light easily passes through the crystal without encountering any barriers. Thus, pure diamonds are colorless.
Perfection is beautiful but also rare. More often, a diamond's growing environment inside the Earth contains other minerals and/or doesn't maintain the perfect pressure and temperature to foster consistent conversion of carbon to diamond.
Dark inclusions can become trapped inside a growing diamond and make it appear black in two ways:
- Clumps of dark impurities such as pyrite, hematite, magnetite, sulfides, and other iron-bearing materials can be captured.
- Some carbon may fail to convert to diamond and remain in darkly colored graphite form.
Graphite inclusions can become particularly noticeable when exposed to high levels of heat in the Earth. According to the GIA, graphitic inclusions can grow up to sixteen times their original size if heated above 1200° C. So, diamonds heated to this degree don't need that many individual inclusions for the whole stone to appear black.
In a 2003 Gems & Gemology article, Sergey B. Titkov et al. wrote that Siberian black diamonds are colored by unusually high numbers of dark magnetite inclusions. This made some of the diamonds slightly magnetic. In a 2019 Gems & Gemology article, Sally Eaton-Magaña et al. reported that 39% of the Fancy Black diamonds examined for their study were colored by crystal inclusions alone. Another 23% were colored by clouds, defined as groupings of impurities mere pinpoints in size.
Exposure to high levels of natural radiation can also make diamonds appear black. Ordinarily, radiation makes diamonds green by creating GR1 defects, locations where individual carbon atoms have been pushed from their regular position in the atomic formation. This leaves green stains on the surface of the diamond. If heated to at least 500-600° C, the green stains on irradiated diamonds turn brown. Such stones are rare, and the presence of radiation stains proves these diamonds are natural and untreated. This feature can't be duplicated in a laboratory setting.
In a 2018 Gem & Gemology article, Karen V. Smit et al. noted that some black diamonds from Zimbabwe owe their color to both the presence of graphite and exposure to high levels of radiation. Eaton-Magaña et al. reported that a total of 27% of the stones in their study had noticeable radiation stains. However, these diamonds were always paired with either cloud or crystal inclusions. Radiation was never the only source of black color.
Other Causes of Black Color in Diamonds
A few rare additional features can also result in a black diamond. Sometimes, clouds of hydrogen and nickel impurities can darken a stone. Some say the absorption of these chemical impurities indicates unusually rapid diamond growth rates.
Black Diamond Trade Names
Trade names are unofficial terms for describing the appearance of gemstones. Dealers use them to help sell their inventory. However, there are no enforceable standards for trade names. Black diamonds have relatively few trade names. You might see the term "gunmetal" used for black diamonds with a hint of gray.
How would you describe a diamond with many dark inclusions and internal fractures but not enough to render the gem opaque and earn the title Fancy Black?
Such diamonds are often referred to by the trade name "salt-and-pepper." They appear transparent and contain a constellation of many distinguishable white, gray, or black inclusions. The diamond crystal itself may be colorless or can appear grayish or whitish due to small clouds of pinpoint inclusions. These large inclusions may be anything found in Fancy Blacks, with graphite being the most common.
The Pros and Cons of Salt-and-Pepper Diamonds
Salt-and-pepper diamonds are one of the most affordable diamond varieties. Because of this, many lack grade reports. However, if you do find a black diamond with a grade report, you'll notice a low clarity grade, often I2 or even I3, the lowest possible grade. This means the diamond is especially susceptible to chipping and breaking. On the other hand, salt-and-pepper diamonds are visually dynamic and, fortunately, easy to replace.
Historically, salt-and-pepper diamonds, like Fancy Blacks, were not used in jewelry. Many considered the inclusions unattractive, and the inclusions weakened the stone. Yet, in recent years, buyers have come to admire these diamonds for their unique beauty. Indeed, no two stones look the same. Some cutters lean into the uniqueness of salt-and-pepper diamonds and fashion them into unconventional shapes to showcase those special inclusions. Cutters often limit the number of facets to minimize internal reflections. This allows the viewer to admire the beauty created by the natural placement of inclusions.
While the term "salt-and-pepper" has emerged as the most commonly used term for these diamonds, you may also see trade names like "galaxy," "misfit," "raw," and "wild."
Identifying Black Diamond
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).
- Dispersion is not applicable for black diamonds.
- The specific gravity (SG) of black diamonds is 3.52 (+/- 0.10), but carbonado diamonds have a notably lower density due to their porous nature.
Since light doesn't pass through black diamonds, looking at a stone through a spectroscope is largely useless.
Black diamonds often don't often fluoresce. However, a few rare stones will glow a weak yellow color under longwave UV light. (Eaton-Magaña et al. reported that the carbonados they examined did not fluoresce).
While black diamonds are mostly opaque, you might see a speckled appearance under magnification and pick out some inclusions that are more lightly colored than others. These inclusions are present throughout the whole body of the stone, not just its surface layer.
Graphite is the most common inclusion. Pyrite and hematite, both minerals which iron in their chemical structure, are also commonly observed features. Black diamonds may have other iron-bearing materials or some sulfides as inclusions. (Pyrite is the most abundantly encountered sulfide inclusion).
Are There Synthetic Black Diamonds?
There have been some successful attempts at growing Fancy black diamonds. Using the chemical vapor deposition (CVD) technique, scientists created diamonds with such a high concentration of nitrogen-vacancy (NV) centers (locations where an individual nitrogen atom sits next to a vacancy where a carbon atom should be) that the stones appeared to be black. These diamonds often appear reddish under strong transmitted light. CVD diamonds may not require any post-growth treatments to concentrate the black color.
Shoppers may find sizable lab-grown black diamonds for a modest price. However, there are many natural black diamonds on the market. This is because the per-carat values of black diamonds are relatively low, so scientists often focus on synthesizing more profitable colored diamond varieties.
Black Diamond Enhancements
Although black diamonds have relatively low per-carat values, many of those you find set in jewelry have received treatments to enhance their color. Eaton-Magaña et al. state that a full third of black diamonds examined by the GIA are treated. Black diamonds frequently start as low-quality gray gems with internal fractures and many inclusions. When treated with high-temperature/low-pressure, the material lining the fractures in these diamonds graphitizes and becomes black.
Laboratories can also irradiate diamonds and induce a green color so dark it appears black. Since the color of these diamonds comes from radiation rather than inclusions, they will be transparent.
Where are Black Diamonds Found?
Many black diamonds come from the Marange deposit in the Eastern region of Zimbabwe. Another region known for its black diamonds is Siberia in Russia.
All carbonado diamonds come from Brazil and the Central African Republic.
Since salt-and-pepper diamonds are just colorless diamonds with low clarity, they occur wherever colorless diamonds form.
Famous Black Diamonds
The following black diamonds and carbonados have become quite famous for their backstories and/or sizes. Keep in mind when reading about these and other diamonds that some sources conflate black diamonds and carbonados. You may also find conflicting characterizations for some of these stones. As a general rule, compare information about any famous black diamond across multiple sources.
Some gems gain a reputation that reaches beyond their physical characteristics and verifiable history. The Black Orlov, also known as the Eye of Brahman, is one such stone. The story goes that an approximately 195-ct rough black diamond crystal was stolen from an idol in India at the beginning of the nineteenth century. Adding to the gem's reputation, a few of the subsequent owners were rumored to have committed suicide. While some of the details connected to the Black Orlov can't be substantiated, the stone gained a reputation for being cursed.
The Black Orlov, which is actually a very dark shade of gray rather than true black on close inspection, was cut into a 67.50-ct cushion shape. The Black Orlov was most recently sold in 2006 for $352,000.
Mined in India in 1998, the Gruosi Diamond is a 115.34-ct, heart-shaped black diamond. It was named for jeweler Fawaz Gruosi, who is credited with helping boost the popularity of black diamonds in the 1990s.
Thanks to some clever marketing, the Enigma has become one of the most visible diamonds in the world. This carbonado diamond was cut to weigh precisely 555.55 cts. It sold at auction in 2022 for $4.29 million.
Another carbonado, the Brazilian Sergio weighs a whopping 3,167 cts, making it the largest diamond — polycrystalline or single crystal — ever found.
The Spirit of de Grisogono
Weighing 312.24 cts, the Mogul-cut Spirit of de Grisogono carbonado diamond was named after the man who cut the rough. It is now set in a ring amongst more than 700 colorless diamonds. It is thought the rough weighed about 587 cts and came from the Central African Republic.
Black Diamond Sizes
You can find black diamonds in many sizes. Small crystals occur in many locations, and designers often place them in pavé settings. Zimbabwe often produces rough that weighs between five and seven carats.
Although some large carbonado diamonds do appear in jewelry, most only find use in industrial applications. They are so difficult to cut and often so large that jewelry use is just impractical.
How to Care for Your Black Diamond Jewelry
You must handle black and salt-and-pepper diamonds more delicately than other diamond varieties. Fortunately, since black diamonds are opaque, they don't need to be cleaned very often. When the time does come, don't use mechanical cleaning systems like steamers or ultrasonic machines. You shouldn't subject these diamonds to heat or vibrations because of their inclusions. Instead, use a soft cloth with mild soapy water but don't rub the stone too forcefully.
Store any black diamond jewelry away from other diamonds. Diamonds, and only diamonds, can cut other diamonds if left in prolonged contact.
Emily Frontiere is a GIA Graduate Gemologist. She is particularly experienced working with estate/antique jewelry.
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