Applicable to any cuts

The crown height is measured using main crown facets. It is measured for each main facet and then the average, minimum, maximum and deviation values are calculated. The software finds the highest vertex of the whole model (it is one of the vertices of the table) and the lowest vertex of each main facet.

Crown height 1. If the main facet reaches the girdle in its lowest vertex, the height between the found vertices is considered to be the height of the crown for the given main facet, as shown on the figure below.

Crown height 2. If the main facet does not meet the girdle, the corresponding vertex is substituted by the edge of the girdle measured at the azimuth of the lowest vertex of the main facet, as shown on the figure below.

If there are extra facets on the girdle, a virtual model without these facets is created and used for the measurement. To build the virtual model, the extra facets are removed and the neighboring facets are continued until they intersect.

Comprehensive list of the Helium report parameters:

• Position normalization
• Diameters, Width & Length
• Main diameters
• Ratio (L/W) & Girdle Ratio
• Table
• Culet
• Total height
• Crown height
• Pavilion depth
• Upper and lower girdle facets' heights
• Crown height at girdle minima
• Pavilion depth at girdle minima
• Depth and length girdle facets
• Girdle thickness
• Girdle types for cushion as red, yellow, green and blue
• Corner angle width and Corner angle length
• Facets' slope and azimuth angle
• Facets' slope and azimuth angle for rounded fancies (obsolete)
• Azimuths deviation from ideal
• MIC & Girdle to MIC
• Girdle-Table offset (by table axis),
  Girdle-Culet offset (by table axis),
  Table-Culet offset (by table axis)
• Crown painting and Pavilion painting
• Girdle type (obsolete)
• Trapezium parameters
• Extra Facet / Natural
• Twist
• Statistical values

Measurements are used in different systems and tools:

• Lower girdle facets or halves
• OctoNus spread & AGS spread