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Black Diamonds- Rare and Beautiful

Updated on May 24, 2011
Black Diamond
Black Diamond
Black diamond pendant
Black diamond pendant

Black diamonds

Also called carbonado diamonds, black diamonds have become increasingly popular over the last decade.

Natural black diamonds are some of the rarest diamonds in the world- not as rare as natural red, pink or purple diamonds, but definitely rarer than colorless, brown, blue and green diamonds. As a matter of fact black diamonds have been found in only two locations in the world- Brazil and the Central African Republic.

Although black diamonds tend not to sparkle as much as other colored diamonds, their unique beauty has drawn of the attention of celebrities like Carmen Electra, Angelina Jolie, Carrie Bradshaw and Lauren Conrad.

How do black diamonds get their color?

Natural black diamonds owe their color to numerous plate- like inclusions within them. Most of these inclusions have been found to be graphite.

Inclusions are gaseous or other particles that get trapped in the diamonds during their formation process.

Where are black diamonds found?

Black diamonds are found in alluvial deposits in Brazil and the Central African Republic. They are not found in the primary diamond- producing countries like Russia, Australia, India or Canada.

It is believed that because black diamonds are found in alluvial deposits and not in volcanic pipe, their formation does not take place at great depths beneath the earth’s surface like conventional diamonds.

What determines the value of a natural black diamond?

Black diamonds are not graded in the same manner in which colorless diamonds are graded; neither are they graded by the usual color scale for fancy colored diamonds.

There is special scale that is designated for the grading of black diamonds. This scale takes into account both their size and coloration.

Grading of black diamonds

How are black diamonds formed?

The formation process for black diamonds has long been a mystery. They are the oldest and toughest diamonds around, and have a chemical spectrum that indicates that they originated before the formation of the earth. In fact, their high hydrogen atom content is an indication that they may be from a star- like environment.  There are many theories of the origin of black diamonds. Some are listed below.

  • Supporters of the extraterrestrial origin of black diamonds believe that they came to earth during an asteroid event that struck when Brazil and the Central African Republic (the only two known locations of carbonado deposits) were still one continent.
  • Some people believe that shock metamorphosis induced by meteoritic impact at the Earth's surface is responsible for their formation
  • Few people believe that black diamonds originated from the direct conversion of organic carbon under high-pressure conditions in the earth's interior (the most common hypothesis for diamond formation)
  • Others believe that they were formed inside an earlier-generation giant star in our area, that would have long ago exploded in a supernova

The Amsterdam diamond
The Amsterdam diamond
The Black Orlov diamond
The Black Orlov diamond

Unusual properties of black diamonds

  1. Black diamonds diamonds are typically pea-sized or larger aggregates of millions of black diamond crystals stuck together
  2. Black diamonds seem to have a hardness that exceeds conventional diamonds due to the fact they do not cleave along crystal plains
  3. Black diamonds are made of porous material that is typically full of bubbles that appear to result from gases present when the diamonds formed. Conventional diamonds are formed deep within the earth, where the high pressure does not allow gases to exist.
  4. Unlike most of the "white" or other fancy colored diamonds, black diamonds are usually opaque. As a result of this attribute, 'cut' parameters are of little importance with black diamonds, since there is no reflection or refraction of light  which produces the brilliance and fire in conventional diamonds.

Famous black diamonds

The Amsterdam Diamond
This famous black diamond was cut in 1972 by the firm D. Drukker and Sons of Amsterdam. Weighing a modest 33.74 carats, it is cut in a pear shape.

It owes its color to the presence of small graphite grains mainly located in the feathers, and to diffusion mechanisms similar to those observed in storm clouds.

This gem is considered one of the best quality diamonds ever to come into existence.

The Black Orlov

Also known as The Eye of Brahma, this 67.5 carat stone is thought to have been named after a Russian princess, after being stolen from an Indian shrine.

The stone has been exhibited widely, including at the American Museum of Natural History in 1951, the Wonderful World of Fine Jewelry & Gifts at the 1964 Texas State Fair, Dallas, and the Diamond Pavilion in Johannesburg in 1967.

It is mounted in a modern diamond-and-platinum necklace. On October 11th, 2006, the necklace containing the stone figured as lot #433 in a Christie's Magnificent Jewels sale where it sold for $352,000.


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    • megha-agrawal profile image

      megha-agrawal 4 years ago from Pune

      Excellent piece of information!!