June 1, 2007 Carbonados, black carbon formations that resemble diamonds, have been show to have a chemical spectrum that indicates they originated before the formation of the Earth; their high hydrogen content suggests they are from a star-like environment. Since this carbon is only found in two locations on our planet, it may have arrived via an asteroid.
Carbonados, or black diamonds, have long been a mystery. They're the oldest, toughest and rarest diamonds around. Now, some researchers have a theory about its origin, and it's out of this world, literally.
Stephen Haggerty, Ph.D., a geoscientist at Florida International University in Miami, has been studying black diamonds for more than a decade. Dr. Haggerty says, "I feel I have an obsession about them, and I do, it's a challenge." It's a challenge because researchers are still trying to figure out where the black diamonds came from. Traditional diamonds are formed deep in the earth and came to the surface through two volcano eruptions that happened 100 million and one billion years ago. Carbonados are older than 3.8 billion years. "They clearly did not form in the same way that conventional diamonds formed," Dr. Haggerty says.
Most diamonds can be found all over the world, but carbonados are only found in Brazil and Africa. Dr. Haggerty believes black diamonds came to earth during an asteroid event that struck when the two countries were still one continent. "Maybe it is a maverick, or a fringe idea, but no one has come up with an alternative," Dr. Haggerty says.
Carbonados have hydrogen in them, suggesting the diamonds formed in an environment, like a star. When examined under infrared radiation, researchers found a spectrum similar to a type of diamond that exists in space. Dr. Haggerty says, "This is the closest we can match this to." It may take some time for all scientists to accept the idea, but one thing's for sure -- carbonados are the most mysterious diamonds around.
BACKGROUND: The origin of carbonado -- more popularly known as black diamond -- have long been a mystery to scientists. New analysis of the world's toughest diamonds suggests they might have come from outer space, specifically from a star that exploded long ago, called a supernova. Researchers from Florida International University believe carbonados came from a large, diamond-bearing asteroid that may have fallen to earth billions of years ago, when the earth and moon were being heavily bombarded by space rocks.
ABOUT CARBONADO: The term "carbonado" was coined by Portuguese in Brazil in the mid 18th century because it resembles porous charcoal. Carbonado diamonds are so tough that it took a 20-ton hydraulic press to break one. This means it is almost impossible to work carbonado into jewelry settings, since they are too hard to be polished or cut -- except with another carbonado. They get their hardness from their structure. While conventional diamonds are cut from a single crystal that breaks easily along a natural line, carbonados are made of millions of small crystals stuck together. Carbonados were first used to polish Brazilian hardwood before transporting it to Europe. In 1905 it was used to drill the rocks for the Panama Canal.
HOW DIAMONDS FORM: Conventional diamonds are formed deep in the earth, since the carbon requires intense heat and pressure to form diamond. Thanks to a series of volcanic eruptions between 1 billion and 100 million years ago, the diamonds came to the surface, where they can be mined. But carbonado is much older -- as much as 3.8 billion years -- and is found only in Brazil and the Central African Republic. The Florida researchers used infrared synchrotron radiation at Brookhaven National Laboratory to identify very tiny amounts of other elements in carbonado. They found hydrogen, which indicates an origin in hydrogen-rich interstellar space. They believe that carbonado diamonds formed in stellar supernova explosions, which formed large asteroids that traveled through space before landing on earth some 2.3 billion years ago.
The American Astronomical Society, the American Geophysical Union and the Materials Research Society contributed to the information contained in the video portion of this report.