The color of Diamonds
Updated: Aug 16, 2019
We often talk about the carats or the cut of a diamond, but when we determine the value of such a precious gem, we need to consider also its color. Color is one of the fundamental attributes of a diamond.
White or colorless diamonds exist on a scale of many different shades, ranging from brilliant white (or colorless) to pale yellow, going through brownish. These subtle differences are graded on a color scale from D (colorless) to Z (light yellow).
Color scale of Diamonds from D to Z (De Beers)
Experts in the world of diamonds determine the color by comparing a diamond against a master set of diamonds of different colors. Without comparing diamonds side by side, it is very difficult to see the difference between a D and a G. A natural colorless diamond graded D is extremely rare to find. It means that the stone wasn’t affected by any alteration or inclusions. Therefore its price is pretty high. Today 1 carat of diamond in D color and IF clarity amounts $17.250!
The differences between the colors are due to alteration of the Carbon molecule. During the long process of formation of a diamond throughout the years, some alterations may occur, such as inclusions of other elements in the crystalline structure, physical deformation of the crystal lattice, radiation, or a combination of causes. All this affects how a stone absorbs and reflects various wavelengths of light. In the case of the yellow diamonds, the change of color is due to a substitution of a Carbon atom by some Nitrogen atoms. In the case of brown diamonds, the atoms of Nitrogen are distributed in a random way within the crystal.
The fancy diamonds
This name is given to diamonds that present some Nitrogen saturation in their crystalline composition. They have been exposed over billions of years to heat, high pressure, natural radiation and the saturation of natural elements. It is said that just one in every 10,000 natural diamonds can be classified as a fancy color diamond. These incredibly rare processes result in beautiful tones and deep saturations of color: deep yellow, pink, blue, brown, gray, green, orange. In the case of a blue diamond, some atoms of Boron are also present in the lattice structure. Some of the famous colored fancy diamonds are:
The Tiffany yellow diamond of 287 carats was worn lately at the 91st Oscar ceremony by Lady Gaga.
The blue Hope diamond of 45.52 carats was bought by the well-known jeweler, Harry Winston. Later on, he donated the Hope Diamond to the Smithsonian Institution in Washington, D.C.
The pink Star diamond of nearly 60 carats was purchased lately by Isaac Wolf in a New York Sotheby’s auction for $83 million. Quite a record!
This is a special case to be mentioned. The black diamonds can be naturally black, but most of them are white diamonds converted in Graphite over a process of many years. Slowly the atoms of Carbon are precipitated in Graphite. The reflection of the light into these transformed molecules makes them look black. They have lost most of the prime properties of the diamonds and therefore their price is much lower.
This would lead us to say that “a diamond is not eternal”!