Articles and News

King Jewelers Explains Differences Between HPHT and CVD Lab-Grown Diamonds February 18, 2025 (0 comments)

Nashville, TN--Lab-grown diamonds are real diamonds created in a laboratory setting, not formed naturally over millions of years. According to King Jewelers, these diamonds are chemically, physically, and optically identical to mined diamonds.

[Image via istockphoto.com]

In a blog post, the jeweler highlights two main production methods are used:

HPHT Diamonds:

The High Pressure High Temperature (HPHT) method uses extreme heat (around 1,500°C) and pressure (about 1.5 million psi) to crystallize carbon over several weeks, often using a diamond seed. Per King Jewelers, this process can introduce nitrogen impurities, resulting in a yellowish or brownish tint. HPHT diamonds are used in both jewelry and industrial applications.

CVD Diamonds:

The Chemical Vapor Deposition (CVD) method involves placing a diamond seed in a chamber with heated gases (typically methane and hydrogen), allowing carbon atoms to deposit on the seed. According to King Jewelers, this process occurs at lower pressures and takes from a few weeks to months. CVD diamonds typically exhibit greater clarity and better control of impurities, making them suitable for fine jewelry and industrial uses.

Key Differences:

• Quality: HPHT diamonds may display a yellowish or brownish tint due to nitrogen impurities, while CVD diamonds are generally clearer.
• Production Speed: The HPHT process is generally faster, while CVD is more gradual.
• Cost: HPHT diamonds are usually less expensive to produce, whereas the precision required for CVD can increase costs.
• Environmental Impact: Both methods offer sustainable alternatives to mined diamonds, with the CVD process typically having a slightly smaller carbon footprint.

Read the blog post here on their website.