Tags: Grade

How Objective are Diamond Colour Grades?

How Objective are Diamond Colour Grades?

Kenneth Lane 01/05/2020 0
Color grades are not as objective as people would like them to be. Even when the grader is someone as highly respected as the GIA, the color grade can be questioned. Russell Shor, senior editor of the JCK (Jewelers' Circular Keystone magazine), pointed out in their September 1987 issue that sometimes the grades of diamonds change when they are sent back to the GIA for re-examination. In 1995, Shor did a study of five diamonds which JCK sent to three major US gem labs. Only one of the diamonds re...
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How to Grade Diamond Colour ?

How to Grade Diamond Colour ?

Kenneth Lane 01/05/2020 0
Probably the best way to learn to color grade is to ask your jeweler to show you how. He or she will have some loose diamonds, a paper or plastic white grading tray, possibly a set of graded comparison diamonds called master stones and a good diffused (not bare) light source such as a daylight-equivalent fluorescent light. You might be surprised when the jeweler places the diamond upside down on the tray and has you look at the color through the pavilion (the backside of the diamond). This, howe...
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