Diamond Anatomy

diamond - anatomy

Girdle

Girdle is the widest part or the outer edge of a diamond that creates a band along the boundaries of the diamond.

Girdle Diameter

Girdle Diameter is the distance in between the two opposite points of girdles. To calculate the minimum and maximum girdle diameter, number of diameter measurement is taken in consideration. Diameter is expresses in terms of the nearest hundredth value of a millimetre i.e. 0.01mm. The averages of diameter are used to calculate other percentages values such as crown height, pavilion depth, total depth and table size etc.

Girdle Thickness

Girdle Thickness is found on the sides of the diamond where the lower girdle facets meets with the upper girdle faces. It can be described in terms of ‘Thin – Medium - Thick’ etc. When there is no girdle in between the crown and the pavilion it is known as “Extremely Thin”

Table Size

Table size is the flat surface on top of a diamond and is expressed in Percentage (%). It is the longest surface area of a cut diamond.

Crown Angle

Crown Angle is the upper part of a diamond which is found on top of the girdle. It’s the angle of Bezel Facet plane in relation to the table plane. It contains large flat surface on top which is the Table area of a diamond. There are lots of facets below the crown angle.

Crown Height

Crown Height is the height in between the Table Plane and the bezel facet intersection with girdle.

Pavilion

Pavilion is the bottom of a Diamond which is found under the girdle.

Culet

The bottom tip is known as culet of a diamond. The GIA lab describes the average width of a culet to that of the average diameter of a girdle and it varies from ‘None – Small – Medium – Large’ etc. Pointed culet is a term used for a diamond with no culet facet.

Total Depth

Total depth of a diamond is the height or distance in between the table and the culet which is measured in terms of millimetres.

Pavilion Depth

Pavilion depth is the distance is measured from the pavilion intersection with girdle to the culet of a diamond.

Facet

Facets are the smooth areas or the flat faces found on the surface of a diamond.

Half Facet Length

Half facet length is the height of the pavilion facet. It is also the horizontal distance from the closet edge of the girdle to the point of meeting two pavilion mains, which is a relative distance in between the centre of the culet and the girdle edge.

Star Length

Star length is the length of star facet situated at the crown. It is also the horizontal distance from the edge of the table to the point of the star facet which is a relative distance in between the girdle edge and the table edge.

Symmetry

Variation of diamond symmetry is also known as symmetry. These variations include misalignments found in facets that fail to point symmetrical to the girdle. Quality of a diamond cut is denoted on symmetry grades such as ‘Poor – Fair – Good – Very Good – Excellent - Ideal’ etc.