Black diamond is a fancy diamond of deep black color, retaining some transparency and a characteristic silky luster. Unlike other colored diamonds, which mainly derive their color from chemical impurities or defects in the substance's structure, such as nitrogen, hydrogen, and boron, raw black diamonds owe their color to the inclusion of graphite and its clustering throughout the diamond.
Type Ia black diamonds: This type of black diamonds contains a large number of inclusions that give them a dark or black color. Inclusions may include graphite, pyrrhotite, pyrope, and other inclusions that form during the crystallization of diamonds.
Type IIa black diamonds: This type of black diamonds has a minimal amount of nitrogen in their structure, making them cleaner and more transparent compared to other black diamonds. They can form under conditions of high pressure and temperature in the depths of the Earth.