Why is it that some gems are more valuable than others?
Part of it is simple economics – those in the highest demand command the highest price. Why they are in demand, however, is more complicated and has to do with a combination of cut, quality, and color. Today we are going to focus on the different color shades of blue sapphires.
Each colored gem has its own color range. For blue sapphires, colors range from a very light blue to a rich blue so saturated it’s almost black. Tone and saturation play a very important role in determining the color quality of a sapphire, with the most valued sapphires a vividly saturated and brilliant, medium-toned blue.
The graphic on the left shows how saturation and tone play an important role in gem beauty and valuation.
As you can see, moving left to right, the saturation of the color plays an important role in the color of the gem, even while the tone stays the same. The same is true from top to bottom when the saturation stays the same but the tone changes.
It is this interplay between saturation and tone that makes such a difference in color and quality. Of course, as we mentioned above, the most valuable stones fall in the center right, with a deep saturation but a tone that has just the right combination of dark and light to create a luminous medium blue.