Applicable to:

• Brilliant
• Rounded Fancies / Marquise, Oval, Pear
• Rectangular Fancies / Princess, Radiant
• StepCuts / Emerald
• StepCuts / Trapezium
• StepCuts / Triangle
• Unknown cuts

The model`s diameter is measured in 360 directions with the step of 0.5 degrees, because opposite directions apply to the same diameter. The diameter of the model in some given direction is measured as a distance between two parallel vertical planes placed perpendicularly to the given direction as close to each other as possible, so that all vertices of the model lay between these planes. The minimum, maximum and average diameters, width and length, diameters perpendicular to minimum and maximum are calculated using this array of values.

Brilliant

The parameters are calculated for brilliant:

• Minimum diameter
• Maximum diameter
• Average diameter
• Width - Minimum diameter
• Length - Maximum diameter
• Diameter deviation

The diameter deviation in millimeters is a mere difference between the maximum and minimum values of the parameter. In addition to this deviation, there is a relative diameter deviation parameter that is calculated by the following formula: (D_max/D_min - 1) * 100%.

Rounded Fancies / Marquise, Oval, Pear

The parameters are calculated for rounded fancies:

• Maximum diameter
• Length - Maximum diameter
• Width - minimum in the direction +/-10 degree perpendicular to Length
• Minimum diameter

Rectangular Fancies / Princess, Radiant

The parameters are calculated for rectangular fancies:

• Minimum diameter
• Width - Minimum diameter
• Length - minimum in the direction +/-10 degree perpendicular to Width
• Maximum diameter

StepCuts / Emerald

The parameters are calculated for emerald:

• Minimum diameter
• Width - Minimum diameter
• Length - minimum in the direction +/-10 degree perpendicular to Width
• Maximum diameter

StepCuts / Trapezium

The parameters are calculated for trapezium:

• Minimum diameter
• Length - Girdle side width-based length
• Width - extreme in the direction +/-10 degree perpendicular to Length
• Maximum diameter

StepCuts / Triangle

The parameters are calculated for triangle:

• Minimum diameter
• Diameter 1 - Minimum diameter
• Diameter 2 - extreme in the range +-30 degree in the direction 120 degree from Diameter 1
• Diameter 3 - extreme in the range +-30 degree in the direction 120 degree from Diameter 1
• Width - Minimum diameter
• Length - maximum in the direction +/-10 degree perpendicular to Width

Unknown cuts

The parameters are calculated for unknown cuts:

• Minimum diameter
• Width - Minimum diameter
• Length - extremum (minimum or maximum) in the direction +/-10 degree perpendicular to Width
• Maximum diameter

All parameters that are measured in millimeters have corresponding percentage values. These percents are calculated relative to average diameter for brilliant or width for other cuts.

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