Just as for carat weight, a standard of grading color became accepted throughout much of the world. The system this course recommends and teaches is the Gemological Institute of America (GIA) color grading scale. It is internationally recognized and in its design it is more detailed, thus allowing the trade to further sort and classify this extremely diverse gem. It is based on (relative) rarity so it makes sense to divide the many color groups into individual and precise grades.
As soon as a demand developed for these gems, there was a need to grade them for valuation purposes. It’s important to be aware of the other systems that are still in use today, so that you can have the ability to communicate, understand, and translate their terms into GIA language. The GIA scale begins with the letter “D” so as to not confuse A, B and C with other scales that are used in the jewelry industry. What the GIA scale includes are colorless (“white” grades) and typically varying shades of yellow, brown and/or gray.
The presence or lack of color will determine the grade, which is expressed as a range value in the scale, in contrast to a firm point on the scale. So if a dealer were to say that a diamond is a high “F”, almost an “E”, this could very easily be an accurate description. Of course in this industry (along with most others), there is often an element of exaggeration in a product description to make it appear more valuable than reality allows.
A direct comparison of the different international color grading scales. As you can see, there is no exact correspondence between any of them. GIA’s scale is the one that this course recommends for primary grading.