What Gives Colored Diamonds Their Color?

As someone working in the diamond industry, I'm often asked what gives the various colored diamonds their coloring:

Broadly speaking, there are two mechanisms that can cause a diamond to come into being with a color other than the more typically thought of white (or to be accurate, clear) color diamond;

Mechanism 1: Corruption from other elements causing color changes Pure flawless diamonds crystals are made only of carbon atoms that are tightly packed in a pattern known as the "lattice". However, during the formation process, the tightly packed lattice of crystal can become embedded with specs of other element atoms other than carbon. Due to the limited space and shape afforded by the lattice only a handful of elements can theoretically take the place of carbon atoms in this way; namely: Nitrogen, Boron, Phosphorus, Hydrogen, Nickel, Cobalt, Silicon, and Sulfur. Such element "corruption" lend the diamond a distinct tint, with higher degrees of corruption leading to higher degrees of coloring;
Mechanism 2: Deformation of the carbon atoms causing color changes The second way for a diamond to gain a different color, is from environmental factors causing a changes in the actual structure of the carbon atom particles (i.e. change in electrons) or in the layout (spacing, symmetry, and pattern consistency) of the lattice. Such examples of environmentally caused deformation include the impact of traveling to earth surface and radiation exposure.

Blue Diamonds are caused the presence of boron atoms in the diamond lattice.

Yellow and orange diamonds are caused by the presence of nitrogen atoms in the lattice.

Brown diamonds are caused by an irregular microscopic pattern of the lattice, essentially a rough diamond. Nitrogen corruption can also cause a brown shade.

Green diamonds are usually caused by radiation exposure! Unlike deformation changes, the change is only to the superficial particles, therefore one should be careful polishing a green diamond as it can lose its color.

Red, purple and pink diamonds Although the precise mechanism is unknown; red, purple and pink diamonds are caused by a distinct deformation of carbon atoms structure (change of electrons) that somehow occurs when traveling through mantle to earth's surface. These colors are among the rarest of the diamond types.

Black and gray diamonds are caused by clusters (not single atoms) of graphite and iron filling large voids in the lattice.

Other color variations and causes exist, and you can have crossovers of the above color changing factors leading to unique shades. There are also many artificial methods for coloring diamonds, but to date all these methods produce results that appear comparatively crude under microscopic inspection, therefore artificially colored diamonds do not carry nearly the same value as their naturally produced counterparts.

About Frank:

I'm Frank (or Franky G as my friends usually call me). I was in the loose diamonds and gemstones business for well over three decades. Now retired, I blog about loose diamonds in order to share my *gems* of knowledge with present and future diamond enthusiasts.

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