Helium help : Comprehensive list of report parameters
Facets' slope and azimuth angles

Applicable to:

  • Brilliant
  • Rounded Fancies / Marquise, Oval, Pear

All facets of the Brilliant, Marquise, Oval and Pear cuts may be divided into layers: main crown facets, upper facets, star facets, main pavilion facets, lower girdle facets (halves)(figure 1).

Figure 1. Facets of a diamond.

Crown and pavilion facets

Facets of each layer are sorted by azimuth, then the slope and azimuth of each facet is estimated. The azimuth is measured in the range from 0 to 360 degrees. The slope is measured in the range from 0 to 90 degrees. Table facet has zero slope (figure 2).

Figure 2. Measurements of slope angle and azimuth angle for the main facet.

Azimuth and slope angles

The slope angle of the crown main facet is the Crown angle in the Helium report.

Figure 3. Crown angle and pavilion angle.

Crown and pavilion angles

DiamCalc Brilliant Cut Parameters