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What are black diamonds?

Black diamond engagement ring

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Black diamonds have a striking appearance, particularly when set against white gold or platinum and paired with white diamonds, and have gained popularity in recent years, particularly for those seeking a unique or unconventional piece of jewellery. 

In this article, we explore the different types of black diamonds, how they get their colour, and the best settings of black diamonds.

What is a black diamond?

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The Enigma black diamond (image courtesy of Sotheby's)

Black diamonds are opaque and have a deep, dark colour that may be black, dark grey or even a deep purple-blue. 

Both natural and treated black diamonds are available in the jewellery market. Natural black diamonds, also known as carbonado diamonds, are relatively rare and so can be expensive, though typically less expensive than natural white diamonds. 

Carbonado diamondites Bangui region Central African Republic
Uncut carbonado diamonds (image courtesy of Wikipedia:

In 2022, the Enigma, a billion-year-old black diamond, which at 555.55ct is believed to be the world's largest cut diamond, has sold for over £3 million!

Unlike other natural diamonds, which were formed in the Earth's mantle, natural black diamonds are thought to have formed in a supernova explosion and arrived on Earth via asteroid impacts, although this is still a topic of debate among scientists.

Treated black diamonds are "normal" (white) diamonds that have been treated to turn them black, and these are more common in jewellery and more affordable. Common treatments for black diamonds include irradiation, heating, and coating.

Treated black diamond
Treated black diamond

How do black diamonds get their colour?

Natural black diamonds get their colour from the presence of numerous inclusions (small imperfections) and impurities within the crystal structure, most commonly graphite, pyrite, or hematite. These inclusions absorb almost all wavelengths of visible light, giving the diamond an overall black appearance.

This makes them different from fancy coloured diamonds, where trace elements in the diamond's crystal structure (like boron for blue diamonds or nitrogen for yellow diamonds) or plastic deformation (in the case of pink and red diamonds) selectively absorb some wavelengths of visible light, but allow others to be reflected and refracted back.

Treated black diamonds are created from "normal" diamonds that have undergone treatments that cause them to turn black. These can include high-temperature treatment that creates or darkens existing inclusions within the diamond, producing the same light-absorbing effect as in natural black diamonds.

Types of natural black diamonds

There are three types of natural black diamonds: Type Ia, Type Ib, and Type IIa. Type Ia black diamonds are the most common, with the largest amount of graphite and other impurities in their crystal structure. Type Ib black diamonds are less common and have less graphite and impurities in their crystal structure. Type IIa black diamonds are the rarest, with the least amount of graphite and impurities in their crystal structure.

Is a black diamond real?

Yes, black diamonds are real diamonds. They are composed of the same carbon structure as traditional white diamonds and are just as hard. Even treated black diamonds, while not naturally occurring, are still real diamonds.

Are black diamonds rare?

Natural black diamonds are relatively rare, estimated to account for just 0.1% of all mined diamonds. 

However, the black diamonds you most often see in jewellery are typically not natural black diamonds but rather other diamonds that have been treated to become black. These treated black diamonds are less rare than natural ones and are generally more affordable.

What settings best compliment a black diamond?

Black diamonds have a bold, dramatic look that can work well with various settings. However, certain settings may highlight their unique features better than others. Here are a few suggestions:

1. White Gold or Platinum: These metals provide a stark contrast to the black diamond, which helps to highlight its dark beauty. This contrast can be particularly striking in a solitaire setting.

2. Halo Setting: A halo of white diamonds surrounding a black diamond can provide a stunning contrast that enhances the black diamond's appearance. This setting can also make the centre black diamond appear larger.

3. Pave Setting: Black diamonds can be used in a pave setting, where small diamonds line the band of the ring. This can be done with black diamonds alone for a uniform look or mixed with white diamonds for contrast.

4. Bezel Setting: A bezel setting, where the metal completely surrounds the diamond, can provide a modern and secure setting for a black diamond.

5. Vintage Settings: Black diamonds can lend themselves well to vintage or antique settings, which can accentuate their unique and dramatic look.

6. Rose Gold: While less common, pairing a black diamond with a rose gold setting can create a warm and unique look.

Remember that the right setting for a black diamond depends on the wearer's style and lifestyle. The setting should not only highlight the beauty of the diamond but also suit the wearer's taste and daily activities.


Is a black diamond a good choice for an engagement ring?

Black diamonds are just as hard as other types of diamonds, making them suitable for use in engagement rings. However, whether a black diamond is a good choice for an engagement ring depends mainly on personal preference. 
Black diamonds offer a unique, bold, and dramatic look. They can be an excellent choice for someone who prefers non-traditional jewellery or wants a piece that stands out. They are just as hard as white diamonds, scoring a 10 on the Mohs scale of hardness, which makes them suitable for everyday wear.
However, there are a few considerations you should take into account:
1. Aesthetics: Black diamonds do not have the same sparkle and fire as white diamonds due to their high concentration of inclusions which absorb light rather than refract it. Instead, they have a sleek, glossy appearance. Make sure this aligns with your aesthetic preferences.
2. Symbolism: In Western cultures, white diamonds have been traditionally associated with purity, innocence, and love, hence their popularity for engagement rings. While increasingly popular, black diamonds don't carry the same traditional symbolism. However, they can symbolise strength, power, and eternal love. 
3. Quality: Most black diamonds used in jewellery are treated to enhance their colour. Natural black diamonds can be expensive and are less commonly used in jewellery.
4. Pairing with other jewellery: If you plan on wearing your engagement ring with other pieces of jewellery, consider how well a black diamond will match them.
5. Design options: While black diamonds can be stunning in the right setting, not every jeweller will have a wide range of black diamond engagement rings to choose from, which may limit your options.
Ultimately, the "right" choice for an engagement ring is highly subjective. If a black diamond reflects your style and you love how it looks, it can be a wonderful and unique choice for an engagement ring.

Are there different types of black diamonds?

Yes, there are two main types:
1. Natural Black Diamonds: These are real diamonds that are naturally black due to a high amount of dark inclusions (most commonly graphite). Also known as "carbonado diamonds", they are found mainly in Brazil and Central African Republic and are relatively rare.
2. Treated or Enhanced Black Diamonds: These are more common in the market. Treated black diamonds start as white or off-white diamonds that have been heat-treated or irradiated to darken the colour, turning them black. The high-temperature treatment process either creates or darkens existing inclusions within the diamond, producing the same light-absorbing effect as in natural black diamonds.

What do black diamonds symbolise?

The symbolism of a black diamond can vary, and often it's up to the wearer's personal interpretation. However, some common symbolic meanings associated with black diamonds include:
1. Strength and Power: Black diamonds have a bold, assertive presence that can symbolise power, authority, and resilience.
2. Passion and Energy: Some people associate the colour black with intense passion and energy, making black diamonds a symbol of strong feelings.
3. Eternity and Constancy: Black diamonds are incredibly durable and long-lasting, like all diamonds. As such, they can represent eternal, unchanging love, making them an exciting choice for engagement rings or anniversary gifts.
4. Uniqueness and Individuality: Black diamonds are less traditional than white diamonds and can symbolise individuality, non-conformity, and a pioneering spirit.
5. Wealth and Prosperity: Despite being less expensive than certain other types of diamonds, black diamonds can still represent wealth and prosperity, as all diamonds are valuable.
Remember, the most important meaning a piece of jewellery can have is its personal significance for the person wearing it. So, a black diamond can symbolise anything that the wearer wants it to represent.


Both natural and treated black diamonds are real diamonds. Natural black diamonds are believed to have arrived on Earth via asteroid impacts. They are relatively rare and are mainly found in Brazil and Central African Republic. Their black colouration is caused by the presence of large amounts of graphite and other inclusions in their crystal structure.

Treated black diamonds are more widely available and less valuable than their natural counterparts. Common treatments for black diamonds include irradiation, heating, and coating.

Because black diamonds are just as hard as other types of diamonds, this makes them suitable for use in jewellery, including engagement rings. However, when shopping for a black diamond, it is important to understand whether the diamond is a natural or treated black diamond and to consider the quality of the stone, as well as the setting and craftsmanship of the piece of jewellery. If you have any questions about choosing or setting a black diamond, please feel free to get in touch. We'd love to help!

David Rhode
Together with Tim Ingle, David created Ingle & Rhode to offer a better alternative to the traditional luxury brands. Since 2007, we’ve provided our customers with genuinely ethical engagement rings, wedding rings and fine jewellery – free from conflict diamonds, dirty gold and child labour. With more than 16 years experience in the jewellery industry, David has deep expertise in diamonds, gemstones and jewellery design and manufacturing.