Fancy Color Diamond Work-Flow

Red diamond with color changed by multiple treatment

Imagine to mix the brilliance and the fire typical of the diamond with the amazing colors of the colored gemstones. The nature is able to combine these amazing characteristics and the result are the fancy color diamonds.  The spectrum of the colors of diamonds is much wider than we usually imagine. It’s possible to find them red, blue, green, pink, yellow, orange, black or brown, with different tones and saturations and, thanks to their wide rainbow of colors, they can satisfy any taste, even the more sophisticated.

Fancy color diamonds are as beautiful as they are very complicated to analyze. Each one of them is a small world that needs to be accurately analysed to understand if it is a natural, a laboratory grown, a color-treated or a natural color diamond. It doesn’t exist a fixed workflow for fancy color diamonds, it depends on their color and step by step from the results carried out by each analyses.

The basic investigation however, as for the colorless diamonds, is a meticulous analyses of the Diamond Type. Depending on it, one of these three scenarios can be opened: natural and natural fancy color diamond, natural but treated-color fancy color diamond, laboratory grown fancy color diamond.

Each color has its own color causes and rules and basing on these, the next necessary analyses will be chosen. The starting point is clarifying if the Diamond Type is compatible with the color itself of the diamond. All the following analyses are intended to identify the crystal lattice centers (or defects) that cause the color and to interpret them. 

One of the first analyses carried out is a high-resolution fluorescence and phosphorescence imaging, which allows to highlight the growth structures of the diamond, a very important data to distinguish between natural and laboratory grown diamonds. 

The focus of the subsequent examination is then represented by the PL analyzes, they permit to verify whether the color of the diamond is natural or enhanced. Numerous analyses are carried out and they are performed both at Room Temperature (RT) and at Low Temperature (LT). For the LT-PL it is necessary to analyze the diamond loose, not mounted in jewellery pieces, since it’s necessary to immerge the stone in liquid nitrogen and reach the temperature of 77K (-200.15 °C). It’s thanks to the study of the results of all the PL analyses that it’s possible to identify if there are lattice synthetic centers related or lattice treated centers related.  

So, if you have a fancy color diamond, it’s really very important to verify whether its color is natural or due to treatment: the value changes in a dramatic way and with the latest techniques applied to treat diamonds, it’s almost always impossible to understand if something happened to your stone only looking at it or also carefully observing it with a microscope. Sometimes to reach the diagnosis takes a long time and many analyses, even applying the most sophisticated techniques and instruments.

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