Master stones lined up in a grading tray with the whitest to the left and darkest to the right.

In using masters, arrange them in your color grading tray with the whitest to the left and the darker to the right. Allow enough space between the masters to insert the diamond in question. You might already have a pretty good idea of its color grade, so you may find it necessary to place just a couple of your masters in your tray. Many dealers and/or gemologist that often grade color in an office or store, will leave their masters in place to save the time in repeatedly setting them up. Of course security is a factor and should be considered whenever diamonds are left out in the open.