The Role of Nitrogen in Colouration
The colour of orange diamonds is closely linked to the presence of nitrogen-related defects within their crystal lattice. These defects are similar to those found in yellow diamonds but contribute to a subtle yet noticeable difference in colour. Nitrogen is the key element that influences the colour of both orange and yellow diamonds by absorbing light in the blue spectrum.
What Makes Orange and Yellow Diamonds Different?
While both orange and yellow diamonds are affected by nitrogen defects, the specific nature of how they absorb light sets them apart. In yellow diamonds, nitrogen-related absorptions occur primarily at wavelengths shorter than approximately 510 nm. This creates their iconic yellow colour. However, in orange diamonds, these nitrogen absorptions extend further into the visible spectrum, reaching up to around 600 nm. This subtle shift in the absorption window is what gives orange diamonds their distinct and captivating orange hue.
The Secret to the Fiery Hue of Orange Diamonds
The orange hue in diamonds appears when the absorption of light stretches further into the red part of the spectrum, allowing the diamond to take on its vibrant colour. This makes orange diamonds not just rare but also highly prized for their fiery brilliance.