Black diamond is also called Carbonado.

Black diamonds are much older than white diamonds or colored diamonds on earth, but their discovery is recent since it dates from the mid-nineteenth century (find out more) and the interest of the public and jewelers is even more.

First black diamonds were used in jewelry in the twentieth century only and it's only very recently that they have really started to gain value in the gemstone market.

Black raw diamond

Black diamonds (carbonados) brut and black diamond cut

 

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View of raw black diamonds in their natural shape and a black diamond cut to be used in jewelry making.

 INDEX

  1. Origins and composition of black diamonds
  2. How to recognize a natural or treated black diamond ?
  3. Black diamond prices
  4. Buying a black diamond
  5. How to associate black diamonds with jewels

 

engagement ring black diamond engagement ring black diamond engagement ring black diamond

 

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Origin and composition of black diamonds

If the process of diamond formation is well known and understood by scientists and gemologists, the origin of black diamonds is still surrounded by mysteries.

Indeed, white and colored diamonds (there are blue, yellow, green and pink diamonds ...) are formed in the bowels of the earth under conditions of very high temperature and pressure, between 150 and 250 kilometers of depth in the Earth's mantle.

Therefore, only volcanic eruptions are likely to "bring us" these diamonds to the surface. This is why diamonds are always associated with kimberlite, a volcanic rock.

Kimberlite volcanic roc

Kimberlite rock containing a translucent rough diamond

But the case of black diamond differs.

Rough black diamonds are found outside volcanic rocks, and black diamond mines are scattered on Earth, so the most recent scientific theories place the formation of black diamonds in space.

They would have arrived on Earth brought by meteorites during the formation of it it is more than 2 billion years. Read this article to learn more about the subject.

The two main sources of black diamonds in the world today are Brazil and the Central African Republic, formerly stuck together when only one continent, the pangea, emerged from the waters 200 million years ago. (Jurassic era).

Natural black diamond composition

Still, natural black diamond differs not only in its color, but also in its composition from other diamonds.

The latter are composed of a regular crystal lattice of light-transmitting carbon atoms while black diamonds are a very porous aggregate of diamond microcrystals with inclusions of graphite and hematite.

As a result, natural black diamonds are as tough as other diamonds, but their composition makes them even more difficult to cut than other translucent diamonds.

The absence of a cleavage plane makes it more complex, resulting in a high loss rate when buying rough black diamonds for polished faceted black diamonds.

These characteristics explain that it is a rare and expensive gemstone.

Treated black diamond 

More conventional, current and especially economic, black diamond most often found in jewelry is a diamond (white or colored) that has been treated to become black.

In the past, this treatment consisted of heating the diamond while the most modern and most commonly used technique now is radiation treatment.

black diamonds

Melee of black diamonds between 1 and 5 points (fr)

These commercial grade diamonds were irradiated. They are commonly used for tessellations on white gold jewelry rings.

These diamonds are much more economical because they are generally diamonds that have many inclusions or colors that can not be used on the market (colors K, L, M ...)

How to recognize a natural black diamond ?

It's the behavior of the black diamond treated with the light which will betray its nature. By directing a source of intense light on an edge of the black diamond that you observe, you'll see that the diamond appears dark green and not black: it's the footprint of diamond radiation treatment.

For this purpose, an optical fiber is normally used to apply the light to a precise location on the edge of the diamond.

Natural black diamonds are opaque by nature and therefore don't allow to observe this phenomenon.

What are the quality and value criteria setting their price ?

Because of its opacity, the famous 4C rule used to evaluate the quality of white or fancy diamonds is not valid.

Indeed, the value of these diamonds depends particularly on their color evaluation, the number and visibility of inclusions and their cut quality, three criteria that make no sense in the case of black diamonds.

So we use the quality scale from A, AA to AAA, the latter value for the highest quality diamonds.

What do we look at to evaluate the quality of black diamond ?

To evaluate a black diamond, one must look at the homogeneity of the color on all the faces and the polished state of the latter, to make sure that they don't comprise pores or stripes.

If you plan to buy a natural untreated black diamond, considering their price, choose to opt for a certification report from an independent laboratory.

evaluating black diamonds chart

Comparison of black diamonds quality (source)

Black diamond price

To get an idea of ​​black diamond price, we can compare the price of a 1 carat round diamond :

  1. HSI white round diamond of 1 carat: from 4500 dollars
  2. 1 carat natural round black diamond starting at 400 dollars
  3. Black treated round diamond from 1 carat from 100 to 400 dollars

This comparison is only indicative but gives you an order of magnitude to guide you in your choice of diamond.

Prices fluctuate according to suppliers, their stock and market demand over time.

How to buy a black diamond 

The first option would be to order your black diamond from your jeweler, he has the necessary contacts to meet your wishes.

Otherwise you can also order online since there are now many suppliers on the web, mainly in the US, Israel or India.

The simplest before making a big order is to order a small diamond to ensure the seriousness of the company, see the shipping and any customs fees.

Once you have made your trial purchase, you can order your diamond with confidence.

Different American sites allow you to buy your natural black diamond online :

  • MySolitaire.com offers black diamonds of all sizes and prices
  • Langerman exclusively offers exceptional black diamonds, resulting in high price
  • Leibish offers natural black diamonds starting at $ 2,500.

There are others, a search on the web will help you to broaden your search.

Be careful when making your purchase, black diamonds are often advertised as natural because they are, but their color is due to the treatment. Look carefully in the description of what is said about the color, whether it's natural or obtained by treatment.

How to associate them with jewelry ?

If black diamonds aren't dazzling stones, they are ideal contrast stones. They'll go perfectly on a white gold ring, yellow or pink or even on a rhodium silver ring, even if we see them most often mounted on white gold.

Mounted in combination with white diamonds, black diamonds are the most beautiful effect.

black diamond ring

Mayanna white gold and diamond alliance from Vivalatina collection with a main black diamond (fr).

 

Free Bonus : Download our complete guide on Diamond (fr).

You'll discover all you need to know to buy diamonds jewelry online or in store.

For further :

August 07, 2019 — Hugo Maherault

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