What is high carbon diamond?

High carbon diamond is a kind of improved cubic zirconia with excellent quality. Cubic zirconia is a synthetic compound. Its molecular formula is ZrO2. Cubic zirconia is not zircon. Zircon is a natural gemstone. Its molecular formula is ZrSiO4, called Zirconium Silicate.

The Mohs hardness of cubic zirconia is 8 vs 10 of diamond. Although softer, it is harder than many other gemstones. It is scratch resistant after being polished and mounted on jewelry set. For your information, Mohs hardness of stainless steel is around 5.5, iron 4 to 5, gold and silver 2.5 to 3.

The quality of a diamond is determined by four Cs - cut, carat, color and clarity.

As an artificial gemstone, a high carbon diamond can be made as big as possible. In comparison, large-sized natural diamonds are rarely found on earth, thus very expensive.  

A colorless natural diamond is rare. The vast majority of natural diamonds have some colors, yet high carbon diamonds can be made to reach the highest colorless grade of D. In addition to colorless, high carbon diamonds can be created in a huge variety of colors, including purple red, purple blue, golden yellow, light yellow, garnet red, olive green, apple green, champagne, pink, etc.

The higher clarity grade, the better. Lower clarity grade is associated with impurity substance inclusion that negatively affects the appearance of a gemstone. A flawless natural diamond is rare, but a high carbon diamond can be made perfectly transparent, with a clarity of VVS or higher.

The refractive or refraction index of an optical medium indicates how much the path of light is bent or refracted, when entering the medium. When the light is reflected in a gem, it will cause a brilliant visual effect. Natural diamond is a gemstone that has the highest refractive index on earth of 2.42. Cubic zirconia has a little lower refractive index 2.15-2.18.


Dispersion is defined as the decomposition of white light into constituent colors (red, orange, yellow, green, cyan, blue, purple) when passing through a medium. The higher the dispersion index, the more rainbow-like brilliance, as known as “fire”, will be observed. Natural diamond has dispersion index of 0.044. Cubic zirconia has higher dispersion index of 0.058-0.066, which appears more glistering than natural diamond.


As we can see, the optical property of cubic zirconia closely resembles natural diamond. At minimum cost, the overall appearance achieved by wearing a set of cubic zirconia jewelry has met or exceeded a set of natural diamond. This fact explains why cubic zirconia is so popular. Not only ordinary people wear cubic zirconia (CZ) jewelry, but also those who own genuine diamonds wear adornments made of cubic zirconia.

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