How to Identify a Black Diamond | By Yourself

How to Identify a Black Diamond

Black diamonds, also known as carbonados, are a unique and rare form of diamond. Unlike traditional diamonds, black diamonds have a dark, opaque appearance and are highly sought after for their unique aesthetic appeal. However, identifying a black diamond can be challenging, especially for those who are unfamiliar with the mineral’s characteristics. In this article, we will explore the various methods used to identify a black diamond.

Understanding Black Diamond

Before delving into the methods of identifying a black diamond, it is essential to understand what a black diamond is and how it is formed. Black diamonds are formed in the same way as traditional diamonds, through immense pressure and heat deep within the Earth’s mantle. However, black diamonds contain numerous inclusions, such as graphite, sulfides, and other minerals, that give them their dark appearance.

Visual Examination

Visual examination is the most basic method of identifying a black diamond. This method involves observing the diamond’s color, pattern, and shape. Black diamonds have a dark, opaque appearance, and the color can range from deep black to a dark gray or brown. The surface of a black diamond may appear rough and pitted due to the numerous inclusions contained within the diamond.

Ultraviolet Light

Black diamonds can fluoresce under ultraviolet light, and this can be a useful tool in identifying the diamond. When exposed to long-wave ultraviolet light, black diamonds can produce a green or yellow fluorescence, which can help distinguish them from other black minerals. However, not all black diamonds fluoresce, and some diamonds may fluoresce differently depending on their origin and composition.

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Black diamonds have a higher density than other black minerals, such as onyx or obsidian. Therefore, measuring the density of an unknown black mineral can help determine if it is a black diamond. However, this method is not foolproof, as some other minerals, such as hematite, can also have a similar density to black diamonds.


Diamonds are the hardest known mineral, with a rating of 10 on the Mohs scale. Therefore, if an unknown mineral has a similar hardness to a diamond, it may be a black diamond. However, this method is not entirely reliable, as some other minerals, such as moissanite, can also have a similar hardness to diamonds.

Thermal Conductivity

Diamonds have high thermal conductivity, which means they are excellent conductors of heat. Therefore, using a thermal conductivity meter can help determine if an unknown mineral is a diamond. However, this method is not commonly used for black diamonds, as the thermal conductivity of black diamonds can be affected by their numerous inclusions.


Identifying a black diamond can be challenging, but there are several methods available to help determine if a mineral is a black diamond. These methods include visual examination, ultraviolet light, density, hardness, and thermal conductivity. While each method has its limitations, using a combination of these methods can help identify a black diamond and determine its value. Understanding these methods can help individuals accurately identify a black diamond, whether they are a collector, jeweler, or hobbyist.

Waqas Anjum
Waqas Anjum

Hi everyone I am Waqas (author of this blog) I love writing and sharing great information with the world. Full-time learning and research is my passion. I am committed to delivering my best research and knowledge in the form of weblog quality content. Thank you so much for your precious time.