Top 10 Facts About the Mysterious Black Diamond (Carbonado, Carbonado Diamond)

For me Black Diamond is the most mysterious diamond and perhaps the most mysterious gem ever. There are many differences between conventional diamonds and black diamonds. Black Diamonds / Carbonados do have unusual properties that are hard to explain without including theories about their extraterrestrial origin. According to these theories Black Diamonds have formed in outer space and have traveled to Earth with asteroids.

Things are more complicated than they look on this list but in this list I can't include all details, scientific analyses, and all pros and cons. Studies and analyses of this gem are doing on.
The Top Ten
1 Black Diamond / Carbonado is the toughest form of natural diamond

Like all diamonds, its hardness is 10/10 (I.e. same resistance to scratching). But being the toughest form of diamond means it is the most resistant to mechanical shock, I.e. it doesn't break or crack easy when hit with a hammer, or it breaks less easy than the other diamonds. Black diamonds are extremely difficult to cut and polish.

Your knowledge about gemstones is amazing!

2 Unlike conventional diamonds which are made up of a single massive crystal, carbonados are made up of aggregates of perhaps millions of tiny crystals stuck together, giving it a porous nature

Stephen Haggerty, a geologist at Florida International University in Miami, US, says that their porous structure was one of the features that "first led some of us to think, well, perhaps there has to be a different alternative" (because it's hard to explain how gas became trapped in rocks).
Haggerty and his colleagues believe that black diamonds came from a large, diamond-bearing asteroid that crashed to Earth from space. They also think that black diamonds formed from diamond dust released when a star exploded in a supernova. This explains those tiny diamond crystals (dust) stuck together and the pores.

3 Black Diamond is an impure form of diamond consisting of diamond, graphite, and amorphous carbon

Black diamonds have many unusual properties and these gems might be a result of formation that includes different/unusual conditions, probably in outer space.

4 Lead isotope analyses have been interpreted as documenting crystallization of carbonados about 3 billion years ago

Most scholars seem to agree with that. Well, a difference of 1,000 and even 100,000 years looks insignificant when we talk about 3 billion years. Currently the biggest question is WHERE did this crystallization happen (on Earth or not? ) and not WHEN did it happen.
Crystallization is the process when diamonds form crystals from surrounding materials.

5 Black Diamond is mainly found in 2 regions of the world - Brazil and Central African Republic

Some say black diamond is ONLY found in these 2 regions, wiki including. But some say that a chunk was found in India and another one in Russia. I can't say who is right. But one thing is sure - not in many locations.

Stephen Haggerty from Florida International University in Miami, US, explained that when the large asteroid with black diamonds landed on Earth, South America and Africa were one land mass, which could account for the diamonds showing up on two continents today.

6 There are 6 main theories about the origin of carbonado and 4 out of 6 include outer space (this proportion says a lot - it's hard to explain many things without including space because carbonado's got many unusual properties)

All these theories are hypotheses and not facts but it's a fact the theories exist so this is a legit item.

None of these 6 theories was widely accepted, including the 4 theories about the extraterrestrial origin. You understand that nothing is 100% sure but it might be true because:
We already know that meteorites and asteroids are facts and not fictions, we also know that some meteorites and asteroids came to earth with gems on them. And we also know for sure that there are gems on Mars, on the Moon, comets, and other celestial bodies (I made lists about it). So it isn't completely nonsensical to assume that a gem (black diamond) came from space. Many other gems did come from space so I don't see a reason to exclude the theories of carbonado's extraterrestrial origin.

I added items with some of the unusual properties of carbonado to show that many things are hard to explain without including space.

7 All other diamonds are associated with kimberlite (a rock) but there was no kimberlite next to carbonado diamonds

Because black diamond isn't found in many locations on Earth, it wasn't hard to check and... in neither

place carbonado diamond was associated with kimberlite, the source of typical gem diamonds. Black diamond has never been discovered in the conventional Kimberlite diamond mines of South Africa, Canada, Australia or Russia. If it never occurs in Kimberlite and Lamproite pipes, it doesn't come from deep inside the earth like conventional diamonds.

So probably black diamonds did not form hundreds of miles below the surface of the Earth (in Earth's mantle) where the conditions turn carbon into diamonds. Black Diamonds probably came from space with asteroids and the conditions of their formation were different than those in Earth's mantle where other diamonds form.

8 Typical diamonds contain common inclusions (minerals) of Earth's mantle but such mantle minerals have not been observed in carbonado. In contrast, some carbonados contain inclusions of minerals characteristic of the Earth's crust

These inclusions from the Earth's crust (surface) do not prove formation of the black diamonds in the crust

because these mineral inclusions may have been introduced after carbonado formation. Also, it's hard to explain how exactly did diamonds form in the Earth's crust when diamonds form in the Earth's mantle.

Atypical inclusions found in black diamonds lead again to some of the theories about the extraterrestrial origin - according to some of these theories a large mass with black diamonds fell on Earth about 2.3 billion years ago and this explains why black diamonds are more related to the Earth's crust than Earth's mantle. Black diamonds stayed in the Earth's crust pretty long and had enough time to absorb some minerals from the Earth's crust.

9 No distinctive high-pressure minerals have been found as inclusions in carbonados, although such inclusions might be expected if carbonados formed by asteroid impact, i.e. if formed ON Earth when Earth got hit by an asteroid

This finding somewhat eliminates one of the theories about the extraterrestrial origin - the one that explains carbonado formation ON Earth due to asteroid impact. There are diamonds (but not black) formed this way on Earth - it's when an asteroid hits the Earth and the shock pressures instantly turn the carbon (mainly graphite) in the rocks into diamonds. They are called Asteroid Impact Diamonds, like the ones in the Popigai Crater, in Siberia, Russia. I still can't exclude completely this hypothesis though.

However, lack of high-pressure minerals (such as the hexagonal carbon polymorph, lonsdaleite, etc.) in black diamond kinda excludes its formation on Earth due to a shock asteroid impact.

So carbonado diamonds probably didn't form in the Earth's mantle, probably didn't form on Earth due to asteroid impact... Again, most probably black diamonds formed in space and came to Earth WITH an


10 The new spectral measurements of the carbonado closely resemble those of other diamonds found in meteorites, as well as diamonds seen in space

Too many unusual properties, too many differences between conventional diamonds and black diamonds. At this point it's harder to explain how carbonado formed on Earth than how it formed in space.
The explanation of the supporters of the extraterrestrial origin is:
Black diamonds formed from diamond dust released when a star exploded in a supernova. Black diamond's material source was a supernova which occurred about 3 billion years ago. And "after coalescing and drifting through outer space for about one and a half billion years, a large mass fell to earth as a meteorite approximately 2.3 billion years ago."
Black diamonds might be the aliens of the gemstone family.

The Contenders
11 Another unusual feature of carbonado is the presence of exotic metals, metal alloys, and very unusual minerals, specifically moissanite and osbornite

For example, osbornite is almost exclusively found in meteorites, originally formed in star dust.

12 Sergio, the largest carbonado, was broken up into small pieces as industrial diamond drills
13 The largest Black Diamond ever found is Sergio, found in Brazil in 1895 (it weighs about 1.4 pounds)

It weighs 3,167 carats, or 61 carats heavier than the largest clear diamond, the Cullinan, which was found in 1905 in South Africa.

14 Isotope studies have yielded further clues to carbonado origin: Unlike other natural diamonds, its carbon isotope value is very low
BAdd New Item