With the increased production of synthetic diamonds for use in jewelry, there has been a vast improvement in the color and clarity of lab-created diamonds and an increase in carat weight. Gemologists and jewelers admit that with the improvement of the quality of man-made diamonds, it is becoming increasingly difficult to identify these gemstones, as their chemical and physical properties closely resemble those of natural diamonds. However, for the past 30 years the Gemological Institute of America (GIA) laboratory has extensively analyzed and studied synthetic diamonds to distinguish them from natural ones.
More characteristics in details
The visual characteristics of lab grown diamonds New Zealand that the GIA has identified are based on the characteristics of some of these artificial diamonds. However, keep in mind that, like natural diamonds, not all laboratory-created diamonds will display all of these characteristics. Therefore, the identification of a synthetic diamond should be based on the diamond demonstrating as many of the identified characteristics as possible. Synthetic diamonds made by the CVD process have different gemological properties than the culture material of diamonds created by HPHT in the laboratory.
Diamonds colored by man using the HPHT process often show uneven coloration. This is due to the way that impurities, such as nitrogen or boron, are incorporated into synthetic diamond during formation. Natural diamonds very rarely show any color zoning, but this is not in the geometric pattern shown by diamonds created in the laboratory using the HPHT process. Color zoning in man-made HPHT colored diamonds is related to the different faces of the crystal, resulting in different patterns than those seen in natural diamonds. In contrast, synthetic diamonds created using CVD typically exhibit fairly uniform coloration and banded deformation patterns, and have high clarity with little,
Process and creation
In diamonds created by the HPHT laboratory you can often see the inclusion of solidified molten metal. This looks black and opaque in transmitted light but shows an almost metallic sheen in reflected light. This is because the flux metal alloy used for artificial diamond growth contains elements such as nickel, cobalt and iron. In fact, synthetic diamonds with a high proportion of metallic inclusions can be picked up with a magnet. The artificial diamonds created by the CVD process are formed in a different way. Therefore they do not have metallic inclusions.
If a natural diamond is examined between two polarizing filters placed at a 90 degree angle to each other, a bright pattern of interference or “taut” colors in the form of mosaic or cross stripes will be more gently observed. This occurs due to the stresses that are exerted on natural diamond as it formed in the earth’s mantle or during its eruption to the surface. As man-made diamonds are formed in a controlled environment with no fluctuations in pressure or changes in stress levels, they do not show any stress or weak band stress pattern. The best way in which a consumer can find out if a diamond is natural or created in a laboratory is to always request a certificate when buying the gem.