Guest Articles >> Crystals & Jewelry

Carbonado: The Amazing Black Diamond

By Zeke Nicholson

Traditional diamonds have a fair amount of variation in terms of carat (size), color, and clarity, but there is one particular member of the diamond family that may have an even grander origin story than its classic brethren: “The Black Diamond.”

What is Carbonado

Popularly referred to as “the black diamond,” the Carbonado diamond exists only in Brazil and Central Africa. They are considerably more rare than white diamonds, which have been found almost everywhere. Carbonados have some amazingly unique properties due their polycrystalline structure, akin to many millions of miniature diamonds smashed together into one. The Carbonado does not refract light like a typical diamond, but rather absorbs it, making it black in appearance. In addition, while white diamonds are cut from a single crystal that can be fractured along a natural line, the polycrystalline composition of black diamonds makes them so strong that they require a 20-ton hydraulic press to break. Because they are so difficult to cut and polish, stores that sell diamonds are less likely to carry black diamonds, but they have been nonetheless used in jewelry to a much lesser extent than their refractive kin.

Carbonado Composition and Origin

rough carbonado specimen

But perhaps the most intriguing aspect of the black diamond is its chemical composition. Whereas white diamonds are composed entirely of carbon, black diamonds contain traces of nitrogen and hydrogen. Their chemical make-up, the fact that they have been carbon dated at over 3.8 billion years old (more than 2 billion years older than any other diamond), and their very limited location, has led some researches to make the interesting hypothesis that Carbonados may actually have extraterrestrial origins. Stephen Haggerty, Ph. D, and his team at Florida International University in Miami, have postulated that a stellar supernova provided the heat and energy to create the Carbonados, which were then transported to Earth on an asteroid. At that time, Brazil and Africa were still connected, so the theory accounts for their particular localities. The theory is certainly an interesting one. Though the evidence remains inconclusive, it certainly provides a depth of intrigue to these already remarkable stones. We may never know the exact origin of the Carbonado diamond, but hopefully researchers will continue to uncover more amazing discoveries surrounding this most unique substance.

rough carbonado specimen

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About the Author

Guest post by Zeke Nicholson.


The above guest post is published based on the premise that it will be helpful and informative. The opinions made within it are those of the author and not of The links you may find within this post do not necessarily imply our recommendation or endorsement of the views expressed within them.


Froese says:

Carbonado diamonds, one form of black diamonds, but not the only. Been recovered as meteorite finds, are in private collection, no scientific interest,yet. These finds will change one day, the perspective, of what is there and still to come.

Starmatter (oxids) fused in the crystal, composed out of million microns…..

,,The Absolute Supermeteorites,,

Mike says:

The only problem with these black diamonds is their lack of sparkle, fire and other optical properties that make the real diamonds so attractive. Rather than reflecting and refracting light, they absorb all the visible light that enters their surface. The other difference is related to their crystal structure. They are not singlecrystalline, like the ordinary diamonds. Instead, they are polycrystalline which means that they are composed out of tiny microscopical single crystalline particles. Since these tiny crystals are oriented randomly in space they do not allow for the light to go through the entire specimen.

anon says:

What is the price of Carbonado? Is it comparable to the price of white diamonds.

Mike says:

Carbonados are diamonds in essence. As I said above, they are not nearly as attractive as white diamonds, but the price is not diminished too much as compared to their crystalline relatives. Probably because they are considered exotic diamonds. They used to be cheaper, but now the price seems to have gone up.

sunnyray says:

Thanks Froese and Mike for your interesting comments. I wanted to add a few words on the subject. What I find interesting is the possibility that these stones are of extraterrestrial origin. By collecting a complete infrared absorption spectrum of carbonado diamonds, Jozsef Garai at al. from Florida International University in their paper published in 2006, indicate the interstellar origin for the carbonado diamonds. They managed to conduct their experiments and measure the absorption, despite the fact that all the previous studies failed due to silica inclusions. The measured FTIR spectra revealed the presence of single atom nitrogen and hydrogen impurities. The lack of nitrogen clusters and the presence of hydrocarbon stretch bonds, along with the lack of heavier metals and metal alloys point toward inter-stellar, hydrogen rich, environments. The carbonados have eventually reached Earth surface in a form of meteorites.

Ebony says:

I have one the one that doesn't stick to magnet. It very very slightly glimmers if in right light, otherwise a bench grinder won't even scratch the thing, but I wanna sale it. No paperwork, I just found it in Vegas at a friends house.

hasan awdiriye abdi-hotto farah says:

In some countries in Africa black or dark grey diamond can be inside the white metallic kimberlite, but it can be with other crystalline diamonds. Thank you.

sunnyray says:

Thanks for the comment, hasan. Very much appreciated.

Mike says:

I recently inherited a collection of stones and noticed one that was set aside marked as "black diamond".... its about the size of a golf ball, i do not have any paperwork on the stone either.

sunnyray says:

Hi Mike. It is certainly an impressive specimen, I mean, a diamond of that size, even if it is a black one. Regardless of paperwork, I would suggest consulting an expert gemologist.

Thai Nguyen says:

Dear Sir! I just had 1 natural carbonado (black diamond). I took it from the drill on oil rig ( I am a driller on oil rig). It"s very harden and polish ,someone told me it"s very rarely and quite expensive because it"s quite big . Now I want to sell it but I don"t know where I should sell. Can you give me some consulting about it.

Dr. Hasan awdiriye abdi-hotto Farah says:

What is the interest was kimberlite with more crystals that cannot see the naked eyes but also the alexandrite (purplish) is the interesting gem chrysoberyl crystal. Could you find 50 grs or 250 carats rough natural one. Thank you.

anon says:

What is the price per carat of these diamonds?

sunnyray says:

I'm no expert. I can only say that apparently the most expensive one should be a faceted black diamond of come 500 carats sold for something like 1,700,000 US Dollars.

Dr. Hasan Awdiriye Abdi says:

We in the Horn of Africa encounter sometimes the crystals of alexandrite, chrysoberyl cat's eye and other beryls or corundum, but we can not identify them with diamonds or diamond selector could not clarify them quickly from their hardness!. Thank you.

james briones says:

I have a suspected black diamond carbonado. I can show you the picture and video if you interested just replay.

Dr.Hasan awdiriye abdi says:

Black Diamond or grey diamond could be in Raw diamond which could met points or crystals of Fancy diamonds although all of them were in that one Kimberlite. Thanks God.

walid othmani says:

I have a black diamond .I want to make sure of it

Jama says:

I think i have a black diamond in fact i have few of it.
In case anyone is interested

Kakadiya Group says:

Thanks for sharing informative content about Carbonado Balck Diamond.

Kevin says:

I've found a strike zone and have stuff for sale.

David says:

I found one of these in California its weight 1061g .i dont know where i can get it verified

sunnyray says:

The best way it to find a qualified gemologist. This page can be useful.

safari says:

I found some of thems and tested by raman espectrometer .so i need a man to help.

Tardies says:

Weigh the Damn things. Specific gravity should be 3.52 for white read that they weigh 3.1 to 3.52 yet. Thermal conductivity testers are next then come a scratch pencil .... Yet if you go n chisel your diamond then you have probably messed up your scratch pencil also. Do your research and event get you a sub microscope and take pictures of the structure. And then if you can't get anyone to listen facet the ffuckin rock on your own get a refractometer and the refractive light will be a refractive light index will be 2.42. Have fun hard bull shit business too get into!NASA has a few papers on carbonado. Stephen haggerty as mentioned up top. Lawence Taylor university tennsee,Knoxville. Just read! Then get about 65 k to 150k u.s. and buy a xrf or xrd masspectrometer and chemically anyliz the stone?

Mahdi says:

I hav found two stones, with numerous bubble points, shiny, opaque doesn't allow light through bt at the age with extream light can show some dark greenish. Looks tough bt i broke the smaller one easily. Could these stones be carbonado?

Mahdi says:

Hi there, i am in East Africa.
I have found some kind of a stone matching all the physical descriptions of a carbonado, I mean it looks dark grey or black with numerous bubble pores on its surface, it does not glitter much even if on light but extreme light can show some dark green color at the edges and its opaque except that I broke it with a stone without using much effort.
I also tried home test of heating using a candle light but nothing happens when thrown in ice. Pliz guide me here, cud it be a carbonado??

Martin valdez says:

Carbonados stick to magnet

gibuin godwill says:

i have carbonado diamond for sale any interesteds person so visit my facebook account."carbonado black diamond carmeroon" Infact there are real cabonado diamond and magnetic

Joel says:

Hello sir i have inherited possible the largest black carbonado diamond weight is 7550 carats rough gem!

Anyone is interested you can contact me WhatsApp +639488213712

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