High Pressure and High Temperature Treatment of CVD Diamond to Make Colorful Diamonds*

High temperature and high pressure treatment has emerged as a remarkable method for transforming diamonds into captivating pink ones. The outcome of this treatment highly depends on various elements within the diamond and the specific treatment approach adopted.

Diamonds typically contain nitrogen atoms as impurities incorporated during their formation. These nitrogen atoms are fundamental in determining the color alteration under high temperature and high pressure conditions. When subjected to pressures between 4 - 8GPa and temperatures within 1300 - 1750°C, the diamond's crystal lattice undergoes significant changes. The intense forces cause the nitrogen atoms to shift from their original positions, giving rise to nitrogen-vacancy (NV) centers.

The formation and distribution of these NV centers are crucial. They play a vital role in modifying the diamond's optical properties by influencing how light is absorbed and emitted, thus resulting in the distinct pink color. Additionally, the treatment way, including factors like the duration of the process (from 1 to 300 minutes in some cases), the type of surrounding materials used in the setup, and the subsequent cooling and cleaning steps, all contribute to how evenly and effectively the color change occurs.

In summary, understanding these elements and carefully implementing the treatment enables us to produce not only pink diamonds but also ones with enhanced toughness and uniform color, enriching the allure of these precious stones in both jewelry and industrial applications.