Whether natural or manmade, colored diamonds cover a full spectrum of shades, often created through different types of inclusions or conditions. A recent report highlighted a rare black diamond: The Enigma, a 555.55-carat black diamond auctioned off in Europe.
The diamond was cut for a greater degree of brilliance, despite its opaque appearance. While most black diamonds are manmade, The Enigma is assumed to be the result of a meteoric incident, produced under specific conditions by an asteroid that landed on Earth.
As you shop around for diamond jewelry, understand how black diamonds are created.
Types of Black Diamonds
There are three basic types of black diamonds: Natural, created strictly through organic conditions; manmade, or grown in a lab; and treated, which adds color to a traditional clear diamond. Demand from women’s and the rising men’s jewelry market has resulted in an abundance of this stone, making it one of the most popular varieties of colored diamonds for engagement rings.
Natural Black Diamonds
For most naturally occurring black diamonds, the crystal structure is altered through graphite and amorphous carbon. These impurities enter during the formation process. Unlike other colored varieties, the inclusions present result in a stone that limits the amount of light passing through.
Related to The Enigma, carbonados are a type of black diamond naturally occurring in Brazil and Central Africa. Carbon and graphite are present and historically, it’s assumed that their formation is related to a meteor colliding with the former supercontinent of Gondwanaland. The result looks like a piece of charcoal and can be found in sedimentary deposits, unlike traditional diamonds.
Carbonados vary chemically from traditional diamonds found deeper within the Earth:
- Certain minerals are not present in their composition, although stones have traces of nitrogen, hydrogen and osbornite – indicative of their meteor-related origins.
- These stones are estimated to have formed three to nearly four billion years ago.
- Carbonados do not have a uniform appearance and based on inclusions, vary from a light gray and semi-translucent to solid black. Certain stones may have a mix of shades, occasionally with some green included. Many also have a luster reminiscent of a piece of metal.
As a result of these factors, natural black diamonds are considered a “fancy” colored diamond and are graded on different standards than their clear counterparts. Whether a traditional natural black diamond or carbonado, these stones are extremely rare, which is reflected by the price.
Synthetic and Treated Black Diamonds
Typically, the black diamonds you see on necklaces and engagement rings are crafted in a controlled laboratory environment.
Synthetic black diamonds are formed through conditions designed to simulate nature. These stones will add graphite and carbon to the crystal structure to mimic the darker, opaque appearance of naturally occurring gemstones.
Treated black diamonds – also known as colorless treated black diamond or black-colored diamonds – have the color added through a heat, high-pressure/high-temperature or irradiation-based treatment. The selected stones already have a high number of inclusions and the treatment results in a uniform, sparkling black appearance.
If you’re curious about black diamonds, explore fancy color and lab-grown stones online. To learn more, stop by a Hannoush Jewelers of Connecticut location.