Diamonds have long played an important role in our culture. They are synonymous with status, power, and even love. But beyond their mesmerizing appearance, diamonds hold great value to science for their physical properties.
Today, diamonds are not just found naturally in the Earth. They can be created through the High-Pressure High-Temperature (HPHT) growth process.
In this blog, we’ll examine the HPHT diamond growth process, as well as their properties and uses that help achieve scientific breakthroughs.
What Are HPHT Diamonds?
HPHT diamonds are a type of lab grown diamond created by using a process called High-Pressure High-Temperature. HPHT is one of two types of processes used to create lab grown diamonds, the other being Chemical Vapor Deposition (CVD).
Are HPHT Diamonds Real?
It’s a common misconception that lab-grown CVD and HPHT diamonds are artificial, similar to cubic zirconia. However, that is not the case. Lab-grown diamonds are indeed real diamonds, with identical physical and chemical structures to naturally occurring diamonds. In fact, due to the controlled synthesis environment used for growth, the lab-grown diamonds have less defects and are “more perfect” in terms of crystallinity.
The naked eye cannot differentiate Natural Diamonds from Lab-Grown Diamonds. It requires special high-tech spectroscopy tools and UV or X-ray lights, which are able to distinguish the more uniform patterns and graining of HPHT diamonds.
Understanding the HPHT Diamond Process
The HPHT diamond process works by mirroring the natural process of diamond creation.
Nearly all naturally occurring diamonds on earth were formed billions of years ago through extremely high pressure and temperature. Science shows that diamonds are naturally formed at a distance of 150-200 kilometers below the surface of the earth, where pressure can reach an astonishing 725,000 pounds per square inch (or 5-6 gigapascals) – that is 50 times higher than the pressure at the Mariana Trench in the Pacific Ocean. At these depths, temperatures reach incredible heights (1300-1600 ºC), forming the perfect conditions for diamond making.
In the modern age, we use the HPHT diamonds process to produce diamonds without having to wait billions of years. The core principle of HPHT diamond growth is to simulate the natural geological conditions – specifically, the combination of high pressure and high temperature that transforms carbon into diamonds. By recreating these conditions in a controlled laboratory environment, it is possible to induce the crystallization of carbon into diamond.
The process works like this:
- A diamond seed is placed in a high-pressure cell located inside a specifically designed pressure press.
- The HP-cell is heated to 1300-1600 °C with pressures above 5-6 GPa.
- The molten metal dissolves the high-purity carbon source.
- Carbon atoms precipitate on a small diamond seed crystal, and a synthetic diamond begins to grow.
- After 5-20 days the lab-grown crystal is extracted. The new diamond stone can then be cut and polished to fit whatever application requires it.
In greater detail, HPHT diamond growth takes place in a small capsule inside an apparatus capable of generating very high pressures. Within the capsule, a carbon starting material, such as graphite, dissolves in a molten flux consisting of metals such as iron (Fe), cobalt (Co), or nickel (Ni), which lowers the temperature and pressure needed for diamond growth.
Due to a deliberately created small vertical temperature gradient, the carbon material then migrates through the flux towards the cooler diamond seed and crystallizes on it to form a synthetic diamond crystal. The Crystallization process to grow one or several diamonds occurs over a period of several days to weeks.
Properties of HPHT Diamonds
Because of the process used to create HPHT diamonds, they carry the same or better properties as natural diamonds. These include:
- Color – While HPHT diamonds are typically colorless, they may have a yellowish tint due to nitrogen exposure during formation. Using specific additives, it is possible to change diamond color (and electrical properties) from pink to blue.
- Hardness – Diamonds are the hardest naturally occurring material in the world, and HPHT diamonds retain the same degree of strength.
- Thermal Conductivity – HPHT diamonds are excellent conductors of heat.
- Chemical composition – HPHT diamonds are made of pure carbon, with a cubic crystal structure, just like natural diamonds.
- Refractive Index – HPHT diamonds retain the same refractive index as natural diamonds, giving them the same sparkle and shine.
Despite having virtually the same characteristics as natural diamonds, HPHT diamonds are significantly cheaper to produce than the cost of mining diamonds from the earth. Lab grown diamonds can cost 50-70% less to produce than natural diamonds, making them practical for a wide variety of uses beyond jewelry.
HPHT diamonds are also far better for the environment. The process of mining natural diamonds is not only destructive to local landscapes, but there are significant labor and human rights violations associated with traditional diamond mining.
With lab grown HPHT diamonds, you can be certain that your diamonds have been sourced ethically.
How to Identify HPHT Diamonds
Earlier we answered the question “are HPHT diamonds real?”. While they are 100% legitimate diamonds, it can be difficult for the untrained eye to tell them apart from natural diamonds.
Luckily, there are ways to identify HPHT diamonds. Here are five ways to identify HPHT diamonds:
- Color Distribution – Lab grown diamonds may show an uneven color distribution, due to their production process. Their exposure to nitrogen makes it more likely for them to exhibit a yellowish hue.
- Graining Pattern – HPHT diamonds have a cross shaped structure and distinctive graining pattern.
- UV Light – Under UV light, HPHT diamonds tend to exhibit a fluorescence pattern.
- Inclusions – Lab made HPHT diamonds may have metallic inclusions which are not present in natural diamonds.
Scientific Uses of HPHT Diamonds
While most associate diamonds with jewelry, they have a wide range of scientific applications in addition to their stunning appearance.
At Euclid Techlabs, we are leading the way in producing the highest-quality HPHT diamonds. Our HPHT diamonds have become essential in helping achieve performance breakthroughs for research and industry.
Some applications using HPHT diamonds include:
- 3D Diamond detectors and Beam Monitor sensors for High Energy Physics applications
- Diamond-based detectors for Dark Matter research
- Radiation-tolerant high-power, high-temperature diamond transistors for defense and space applications
- A new line of nanocrystalline diamond-based cathodes
- A single-crystal diamond compound refractive lens (CRL)
- X-ray Phase plates to focus X-rays for next generation light sources
- Diamond capillary manufacturing technology for laser-plasma Wakefield accelerators
- Diamond substrates for the creation of qubits for quantum computing uses
We know firsthand the importance of high-quality components. That is why all our HPHT are held to our own exacting standards for advanced physics applications.
Conclusion
High-pressure, high-temperature diamonds are every bit as real as naturally occurring diamonds. Not only do HPHT diamonds contain all the same physical properties as natural diamonds, but they also offer a far more sustainable and economical alternative to mined diamonds.
At Euclid Techlabs, we are at the forefront of HPHT diamond technology, producing the highest quality lab-grown diamonds for scientific research and applications. Our diamonds and diamond-based applications have been used for groundbreaking research in fields like high energy and nuclear physics, defense, space exploration, medicine, and more.
Ready to explore the potential of HPHT diamonds and diamond applications in your organization? Contact Euclid Techlabs to discuss your specific needs and learn how our cutting-edge diamond technologies can elevate your projects.