Trinity Peng - August 1, 2023

How Do Lab Grown Diamonds Get their Color?

Lab-grown diamonds acquire their color through the intentional introduction of certain trace elements during the diamond growth process. The addition of these elements imparts specific colors to the diamonds. It's important to note that not all lab-grown diamonds are intentionally colored. Many lab-grown diamonds are grown without any additional colorants, resulting in a colorless or near-colorless appearance, similar to high-quality natural diamonds. Additionally, the color grading of lab-grown diamonds follows the same GIA (Gemological Institute of America) scale as natural diamonds, which ranges from D (colorless) to Z (light yellow or brown). Fancy colors, like blue, green, pink, etc., are also graded on a separate scale based on their intensity and hue. Here's how it works:

Yellow and Brown Diamonds

The most common color seen in lab-grown diamonds is yellow, which is achieved by introducing nitrogen atoms during the growth process. Nitrogen impurities absorb blue light, resulting in the diamond reflecting a yellow color. Depending on the concentration of nitrogen and the specific growth conditions, diamonds can range from light yellow to deep brown, also known as "fancy yellow" or "cognac" diamonds.

Blue Diamonds

To create blue lab-grown diamonds, boron is introduced during the diamond's growth. Boron atoms interact with carbon atoms, causing the diamond to absorb red, yellow, and green light, while allowing blue light to be transmitted, resulting in the blue color.

Green Diamonds

Green lab-grown diamonds are produced by exposing the growing diamond to radiation, typically in the form of electron beams. This radiation treatment alters the diamond's crystal structure and causes it to exhibit a green color.

Pink, Red, and Purple Diamonds

The most common way Pink, Red, and Purple diamonds are created is by exposing a lab-grown diamond that was grown with nitrogen impurities to radiation, known as irradiating. Afterward, the diamonds are subjected to  temperatures ranging from 600°C to 1000°C. 

Other Colors

Lab-grown diamonds can also be created in various other colors like orange, gray, and black. The introduction of specific impurities or defects during the growth process can lead to these unique colors.