CHANGE THE COLOR OF DIAMONDS THROUGH CUTTING
By Joe C. C. Yuan-- G.G., D.G.A.
When we looking at two diamonds, one is round brilliant, another is fancy shape. As we compare through the bottom, two diamonds are same color, but from top view, the fancy shape is more yellowish or darker than the round one. This is because all the pavilion facets of the round brilliant cut diamonds are arranged within good angles, its reflection and brilliance on top are strong and even. Good reflection automatically cover some yellowish in the body color of the stone. On the contrary, the pavilion facets of the fancy shape diamond are not all in good angle range, some deeper, and some flatter than the ideal angles ranges. We can see some part of the top with more body color.
Even two round brilliant cut diamonds, if the proportion of cutting is different, it will show different body color on top. Better make diamond shows more reflection and brilliance, which will reduce more body color. On the contrast, poor make produce less reflection and brilliance the body color is more visible.
On the different tone of the color diamonds and different thickness of the stone, there are different shapes, angles, and facets arranging to match different kinds of stones.
The angles which near the culet should be lower, to cause levels of fish eye effect. That can absorb more light to go through. But weight can maintained by cut steep angle level facets near the girdle. On the crown, keep the crown angle very steep, so one can easily see most bottom through every crown facets. Which in turn will allow more light be reflected back.
Fig. 8-1 shows a poorly made brilliant round diamond that was dark brown color and deep in thickness. Fig. 8-2 shows the Solstar™ 168 cut to improve the brilliance and color of the stone.
The best way of cutting stones that are darker in color and deep in thickness is to cut in good make or modified brilliant round, princess, trillion, heart, very flat on the bottom angle of radian cut.
To lighten the color of the diamond, we can go able few different ways., One is to reduce the bowtie on fancy shape diamonds. Another method is to make the bottom angle shallow, but normal on crown angle. One other way is to cut in good make or modified brilliant round, princess, and trillion.
Since fancy shaped stone tends to be darker in reflection, when we need to darken a stone, we should make fancy shape if possible. The way to achieve the darken the stone is make the bottom steeper and keep the bowtie. Another way is to leave the girdle thicker and make the crown angle steeper. Avoid better reflection and brilliance shapes. If shape of rough is near square, make step cut, instead of brilliant cut.
To darken the color on fancy shape stones, one should keep medium size bowtie if possible. This will maintain some darkness in color and not the brilliance. Avoid better reflection and brilliance shapes.