Diamonds take shape under extreme heat and pressure. Their color is shaped by minuscule impurities or defects in their crystal makeup. Nitrogen atoms are a major factor. When they embed themselves in specific spots within the diamond’s crystal structure, they alter the diamond’s optical traits. More nitrogen leads to a deeper yellow or brown hue, while less nitrogen gives a paler yellow or near – colorless look.
Colored diamonds, on the other hand, owe their hues to rare elements, crystal defects, or structural warps during growth. Boron makes diamonds blue, crystal irregularities result in pink, and radioactive elements or radiation yield green diamonds. Given their complex formation, colored diamonds are rarer than white ones.
The International Gemological Institute (GIA) has set the standard for grading white diamonds based on transparency and colorlessness. The scale runs from D to Z.
- D – F (Colorless): These are the pinnacle of colorless diamonds. Grade D is entirely colorless, the rarest and most costly. E and F are also colorless, with differences only detectable under high magnification or by experts.
- G – H (Near – Colorless): Slightly more color is present, but it’s still hard to spot. Only professionals with magnification can easily tell the difference in G – graded diamonds, while H – graded ones show a faint, but not glaring, color difference to the naked eye.
- I – J (Light Yellow/Brown): Here, the color is more noticeable, visible under magnification or in certain lighting for I – graded diamonds, and quite obvious for J – graded ones.
- K – Z: The color deepens significantly in this range, from light to dark yellow or brown, sometimes with a grayish tinge. These diamonds are generally considered to have lower – quality color.
As the color of a white diamond darkens, its ability to reflect light, along with its fire and brilliance, diminishes.
Colored diamonds have a distinct grading system. GIA’s system evaluates them based on the main color, as well as the concentration and saturation of that hue. It has nine levels:
- Faint: The lightest and least saturated color.
- Very light: High lightness, minimal chroma.
- Light: Higher lightness, low chroma.
- Fancy light: High brightness, relatively low chroma.
- Fancy: Medium lightness, low to medium chroma.
- Fancy intense: Medium lightness, medium chroma.
- Fancy vivid: Medium lightness, medium to high chroma.
- Fancy dark: Varying brightness from clear to dark, with low to high chroma.
- Fancy deep: Dark to dark – light, medium to high chroma.
Each main color of colored diamonds has some nuanced grading differences, but all are based on GIA’s system. Natural colored diamonds come in a wide variety of colors, but their harsh growth conditions make them scarce. Lab – grown colored diamonds are more numerous overall, yet technical constraints limit the main colors available on the market, mostly yellow, blue, and pink.
In conclusion, diamond color grading is pivotal for assessing diamond quality and directly impacts how a diamond looks and its market price. Whether you’re eyeing a colorless diamond or a vividly colored one, grasping these grading systems is key when making a purchase, helping you find the perfect diamond to match your taste and budget.
