Diamond color is defined as the amount of color that a diamond has when it is graded in the face down position. In the labs, the grading is performed under strict rules that need to be followed:
– it is done in a controlled lighting environment (using a color balanced light source against a pure white background)
– it must be done by a skilled grader with proper credentials
– using a set of specially graded diamonds of known colors (these are called “master stones”, typically an E, G, I, K, and M)
– the diamond that is being color graded must not be in a ring, earring, etc.
There are some colorimeters (diamond color grading machines) that are being used but most of the labs are still doing it the “old school” way by using Gemologists. Some gemological laboratories have been known to be a bit more lenient in their diamond color grading.
As a result, unethical vendors send diamonds to these gem labs in the hopes of receiving a higher diamond color grade. This could reflect in a 10 to 15% increase in the diamond’s final selling price.
Let Me Share Some Stories About Diamond Color And The Industry
In one of my former lives, I worked for a jewelry importing company in Japan. The owner of the company had the diamond grading reports done by a Japanese gemological lab in Antwerp. When we went on diamond buying trips to Antwerp, the diamond grading reports always turned out with higher diamond clarity and diamond color grades than what I had expected.
Recently, I have seen this happening with diamond grading reports from EGL in Israel.
This demonstrates that not all diamond grading reports are created equally. That is why you should not venture far from reports from GIA, AGSL, or GCAL. Buying a diamond without a diamond grading report or a grading report from an unknown lab is usually not a good idea.
This is especially true if you are considering buying from an online retailer. If you are dealing with a good local retail jeweler and you have a lot of trust in them, then you might consider it. Sometimes a good local (trusted) jeweler can offer you a good deal on a diamond that doesn’t have a grading report.
Many diamond sellers refer to a D color as being the “best” diamond color grade. However, the truth is, there is no best diamond color! A D color diamond is best for the diamond seller because they can charge you more for a colorless diamond!
The pricing level of a colorless diamond is based on rarity factors and not based beauty scales. I personally like a diamond with a bit of “warmth” like a G, H, I, or even a J and this is really up to personal preferences. From experience, I had even seen some beautiful diamonds that were in the M, N, O color range.
In short, you need to use your best judgment when deciding the diamond’s color you are interested in. It largely depends on your budget and individual needs.