16th April 2024

What Are Blue Diamonds and How They Are Formed

What are blue diamonds


What Are Blue Diamonds?


Blue diamonds are a rare variety of earth-mined diamonds. They derive their distinctive blue hue from the presence of chemical elements, primarily boron, within their crystal lattice structure. The boron atoms absorb certain wavelengths of light, resulting in blue colouration that ranges from light to deep or vivid blue tones.


Blue diamonds are highly sought after and considered one of the rarest and most valuable diamond colours. Their scarcity and striking beauty make them a perfect choice for someone looking to wear unique and luxurious jewellery, such as blue diamond stud earrings or blue diamond pendants.


The popularity of blue diamonds has increased in recent years due to several factors:


Celebrity Endorsement


Blue diamonds have received significant attention in the media and among celebrities. Many celebrities, including Jennifer Lopez, Beyonce, Celine Dion, and Kate Winslet, have been seen wearing blue diamonds on the red carpet or at public events, sparking interest in these exquisite gems.


Unique Aesthetic Appeal


Blue diamonds possess an alluring hue that sets them apart from traditional colourless diamonds. Their vivid blue colouration evokes elegance, sophistication, and exclusivity.


Symbolism and Significance


Blue diamonds symbolize purity, tranquillity, and strength, making blue diamond rings a meaningful choice for proposal. Their rarity and uniqueness also add to their symbolic significance as expressions of love and commitment.



How are Blue Diamonds Formed?


Natural blue diamonds are formed when boron is present during the diamond’s formation process deep within the Earth. The boron atoms absorb red and yellow light, causing the diamond to appear blue.


However, blue diamonds are exceedingly rare in nature, constituting only a tiny fraction of all diamonds mined, making them hard to find and expensive.


A more affordable alternative to a naturally blue diamond is an earth-mined diamond that has been treated with high-pressure, high-temperature (HPHT) to change its colour to blue.


During the HPHT process, high pressure and high temperature are applied to the diamond in the presence of specific elements or compounds that can alter its colour. For blue diamonds, boron is introduced during the HPHT treatment to induce a blue hue.



Here’s how the HPHT treatment process works:


  1. Preparation: The diamond is cleaned and prepared for treatment to remove any surface impurities or contaminants.
  2. High Pressure and High-Temperature Conditions: The diamond is exposed to extreme pressure and temperature conditions in a controlled environment, replicating the natural conditions under which diamonds are formed deep within the Earth’s mantle.
  3. Introduction of Boron: Boron, which is responsible for the blue colour of diamonds, is introduced into the crystal lattice structure during the HPHT process. The boron atoms replace some of the carbon atoms in the diamond’s structure, resulting in blue colouration.
  4. Cooling and Stabilization: After achieving the desired colour change, the diamond is slowly cooled to stabilize its new colour.


An earth-mined diamond that has been treated with HPHT to change its colour will still test as a naturally mined diamond. The treatment is permanent and non-reversible, so the diamond holds its value.