GIA 4Cs Color
Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value. (The exception to this is fancy color diamonds, such as pinks and blues, which lie outside this color range.) Most diamonds found in jewelry stores run from colorless to near-colorless, with slight hints of yellow or brown.
GIA’s color-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown. Each letter grade has a clearly defined range of color appearance. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions.
Many of these color distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.
WHY DOES THE GIA COLOR GRADING SYSTEM START AT D?
Before GIA developed the D-Z Color Grading Scale, a variety of other systems were loosely applied. These included letters of the alphabet (A, B and C, with multiple A’s for the best stones), Arabic (0, 1, 2, 3) and Roman (I, II, III) numerals, and descriptions such as “gem blue” or “blue white.” The result of all these grading systems was inconsistency and inaccuracy. Because the creators of the GIA Color Scale wanted to start fresh, without any association with earlier systems, they chose to start with the letter D—a letter grade normally not associated with top quality.
While many diamonds appear colourless, or white, they may actually have subtle yellow or brown tones that can be detected when comparing diamonds side by side. Diamonds are formed under intense heat and pressure, and traces of other elements may have been incorporated into their atomic structure accounting for the variances in colour.Diamond colour grades start at D and continue through the alphabet. Truly colourless stones, graded D, are extremely rare and very valuable. The closer a diamond is to being colourless, the rarer and more valuable it is.
The colour of a diamond is graded with the diamond upside down before it is set in a mounting. The first three colours D, E, F are often called collection colour. The subtle changes in collection colour are so minute that it is difficult to identify them in the smaller sizes.
D refers to perfectly colourless diamonds. This is the clearest and rarest of the range. E refers to extremely colourless diamonds. Trained professionals can detect a slight tinge of colour but usually even this is undetectable. F refers to colourless diamonds. Trained experts can detect colour. This is the lowest of the colourless grades. G-H are nearly colourless. When compared to better colour grades, a slight colour is detectable, but is a much better value. It is extremely difficult to distinguish a single grade under less than ideal laboratory conditions, even by a professional
Although the presence of colour makes a diamond less rare and valuable, some diamonds come out of the ground in myriad “fancy” colours – well defined reds, blues, pinks, greens, and bright yellows. These are highly valued and extremely rare.
Diamonds are not all truly colorless, but it’s the colorless, often called white, diamonds that other shades are judged against.
Truly colourless stones are extremely rare and valued. This is because their beauty lies in their incredible optical properties. A diamond acts as a prism, separating light into a spectrum of colours and reflecting it as vibrant flashes, called fire. The fewer colours in a diamond, the more colorful the flashes of fire will be. In colourless diamonds, all the colours of the rainbow are reflected back to your eye.
It is not easy to see the difference between two similar grades of diamond, as the distinctions are very subtle.
When directly comparing diamonds for colour, most consumers are unable to detect a difference unless they are at least two or three colour grades apart.