The simulator cut grade shows how a worse make of the same design looks. Each grade moves the crown angle, pavilion angle, girdle, table and culet by a fixed step.
In more detail
It is a picture of a poorer make, not a measured light figure and not a laboratory grade. Poor, for example, lowers the crown angle 2.5° and raises the pavilion angle 5.2°. It also adds 3.5% to the girdle, 13 to the table and 3.5% to the culet.
How we measure it
The tool turns crown and pavilion facets about their girdle edges and rebuilds the table and culet. It rescales the stone to keep its weight. House cuts, the heart and the Platonic solids are shown as designed.
Related terms
- 3D Gemstone Simulator: The 3D Gemstone Simulator is a free Digital Gemology tool that renders a cut stone as a camera sees it. You choose the cut, gemstone, carat weight, color, clarity, cut grade and lighting.
- Cut grade: The cut grade rates how well a diamond's proportions and finish work, from Excellent to Poor. GIA gives it only to standard round brilliants in the D-to-Z color range.
- Crown angle: The crown angle is the slope of the bezel facets, measured against the plane of the girdle.
- Pavilion angle: The pavilion angle is the slope of the pavilion mains, measured against the plane of the girdle.