Hpht vs cvd is a hotly debated topic in the diamond industry. Both processes use diamond growth techniques, but the latter is more expensive and time-consuming. This article focuses on the HPHT process and its blue nuance. Read on to learn more. Is CVD better than HPHT? I’ll explain. But first, let’s consider how these two processes differ.
morphology
In this study, the morphology of HPHT diamonds versus CVD diamonds is compared. In the first experiment, Ib-type HPHT diamond substrates were used with a nitrogen content of 60 ppm. Both nitrogen-doped and non-doped gasses were used as process gases. Following the growth, the diamond substrates were mechanically polished to a roughness of 3 nm, and the seed substrates were acid-cleaned with sulfuric acid-nitric acid mixture.
In the second experiment, the morphology of seed substrates differed between CVD and HPHT. In the former, the growth sectors had extended defects, whereas in the latter, the dislocation density was less than half. The CVD seed substrate allowed the growth of higher-quality diamonds. These differences in morphology suggest that CVD is a more promising candidate for high-quality HPHT seed substrates.
HPHT diamonds are typically yellowish, but the latter are rarer. The two methods are generally considered to be equally efficient for creating perfect diamonds. The main difference between the two processes lies in the impurities a diamond has. While CVD diamonds have a higher price tag, HPHT diamonds are generally more affordable. However, the differences are subtle, and the quality of the end product is comparable.
blue nuance
The blue nuance of HPHT diamonds is a result of the impurities such as boron that are present in these stones. Boron is also a component of fancy blue diamonds. You can view an HD video of these diamonds to determine the degree of blue nuance. The CVD method was invented in the 1980s and mimics the formation of diamonds in interstellar gas clouds. It uses less pressure and smaller machines than the HPHT method.
There is a difference between hpht vs cvd diamonds when it comes to the amount of boron present. HPHT diamonds contain a lower amount of boron than CVD diamonds. While CVD diamonds are more expensive to grow, they also have a higher selling price. Hence, it is best to purchase HPHT diamonds when possible.
Conclusion
Although the difference in the appearance is minimal, blue nuance does exist. This effect is a genuine concern for most consumers. HPHT diamonds are usually found to have a high amount of blue nuance. In contrast, CVD diamonds typically have strain lines, a pattern that identifies them as lab-grown and a post-growth treatment to boost their color. Natural diamonds do not have this blue nuance, and should be screened out for any visual resemblance.
