When More Than One Color is Observed in the Face-Up Position
Additionally, for gemstones that are heavily color zoned, it may be difficult to arrive at a single ColorCodex™ reference. In these instances users should match the overall impression while accounting for the average of the different color intensities. This ColorCodex™ reference should then be accompanied by a comment on the degree of color zoning observed in the face-up position (such as: weak, moderate or strong). If a gemstone is so strongly color zoned as to be considered a ‘bi-color’ or ‘tri-color’, then it is recommended that two (or more) color references are made. For gemstones that are strongly pleochroic, which may reveal more than one color in the face up position, multiple ColorCodex™ references are recommended.