When comparing a hpht vs cvd diamond, the two kinds of gems have some similarities and differences. The main differences are morphology, inclusions, failure mode, and color. We will explore these differences and similarities below. For further information, read our complete article. This article will also give you an overview of the different kinds of diamonds available in the market.
morphology
The most significant difference between an hpht diamonds and a CVD diamond is the morphology of the stone. In simple terms, the morphology refers to the growth pattern of the diamond. HPHH diamonds grow in fourteen directions, while CVD diamonds grow in only one. CVD diamonds gain electrons from the N S defect and are thus brown in colour.
The main difference between the two kinds of diamonds is that the former does not show strain lines and is thus clearer and less cloudy than the latter. On the other hand, CVD diamonds have a slight blue hue that is caused by boron impurities. This difference makes it harder to make an accurate diagnosis of an HPHT diamond. Ultimately, both types are very difficult to distinguish.
The HPHT process is associated with the production of diamonds with yellow or brown colours. While both methods are capable of producing a colourless diamond, HPHT machinery is prone to creating sub-quality items. Therefore, while both methods are effective in creating a perfect diamond, the morphology is the difference between the two types. This article will examine how the two processes differ in this area.
inclusions
The difference between a CVD and an HPHT diamond lies in the way each type of inclusion forms. Inclusions in an HPHT diamond are metals called fluxes that can enter the crystal. Fluxes are often nickel, iron, or cobalt, and larger metallic inclusions are easy to detect with a magnet. CVD synthetic diamonds do not have metallic fluxes, and most of the inclusions are dark graphite or other minerals. Neither type of inclusion, however, possesses the metallic luster of an HPHT diamond.
While the CVD and HPHT diamonds are created through the same processes, HPHT diamonds tend to have black flux inclusions. The differences between the two types of inclusions do not make a big difference in practical terms when choosing a diamond. Neither type of diamond is “perfect” – if a stone has inclusions, it’s probably a CVD.
failure mode
HPHT and CVD methods are two common processes for the synthesis of gem-quality diamond crystals. Though the processes have many advantages, both are not enthusiastically pursued. This is due to their higher costs and impracticality for large-scale production. Today, only few CVD diamond crystals are grown, but these are used in special applications and for military purposes. This article will explore some of the benefits and drawbacks of these two methods.
HPHT synthetic diamonds are usually characterized by metallic flux inclusions. These impurities may consist of nickel, cobalt, or iron. In addition, CVD diamonds typically display banded “strain” patterns. These patterns help differentiate between HPHT and CVD synthetic diamonds. Unlike natural diamonds, HPHT synthetic diamonds do not have these metallic inclusions. Instead, they contain traces of dark graphite or other minerals. However, they do not exhibit the same shimmer.
color
One of the first things to consider when evaluating the color of a synthetic diamond is whether it is HPHH or CVD. While both diamonds are created using the same techniques, the two differ in their chemical composition. The differences are apparent in the PL spectra of HPHT and CVD diamonds. In contrast, the PL spectra of natural diamonds show typical absorption peaks from silicon and aggregated nitrogen. Fluorescence patterns are also very similar between natural and synthetic diamonds.
Conclusion
HPHT treatment improves the color of diamonds permanently. Unlike CVD diamonds, HPHT diamonds are clear and free of strain lines. CVD diamonds are characterized by a faint blue hue, which is caused by impurities like boron. This is a characteristic that distinguishes them from naturally colored diamonds. Aside from color, HPHT diamonds are also known to be higher in transparency than their counterparts.
