Here is a surefire way to recognize Ideal cut diamonds at a glance. Learn to look for the “eye of the diamond”.
The mosaic pattern of reflections in the top portion (crown and table) of a brilliant cut diamond can be subdivided into three concentric rings—each of which corresponds to a part of the eye: the pupil, the iris and the whites. The pupil is the innermost ring in the very center of the table; the iris is the middle ring that extends to the table’s edge, and the whites is the outermost ring in the crown outside the table.
The innermost ring, which is the table’s reflection, dilates like the human eye’s pupil when the diamond is cut with a pavilion that is steeper than ideal, a shallow total depth or too large a table.
When a diamond’s pavilion is ideal cut, its pupil, or innermost ring of reflections will be about a third the size of the table. If this section is larger than one half the table or one quarter the diamond’s diameter, you are not looking at an Ideal cut diamond.
Next, look at the iris, or middle, ring. If this table area appears noticeably greater than six-tenths of the diamond’s diameter, you are also not looking at an Ideal cut diamond.
Remember: In the Ideal cut, beauty is balanced between the three rings of the “eye of the diamond”. This balance gives you evenly distributed brilliance, fire and sparkle across the top section of the gem. So make sure the center ring, pupil of the “eye”, is about one third the size of the table, and the middle ring is less than or equal to six-tenths of the diamond’s diameter.
Can you identify the three rings of the eye in these two diamond photographs? See if you agree with the solutions to their right.