Diamond properties

The Ideal Proportions of a Brilliant-Cut Diamond

In 1919, Marcel Tolkowsky developed a mathematical formula for cutting diamonds into precise angles and proportions to achieve the optimum reflection and refraction of light, optimum stone balance, sparkle and fire. Lazare Kaplan, Marcel’s cousin, adopted the theory and today is still devoted to the art of cutting the most beautiful diamonds in the world.

Today, fewer than 1 percent of the world’s diamonds are ideal cut. To achieve this quality, more of the original rough diamond must be sacrificed. Thusly, there is only a small amount of diamonds that hold up to the standard of the ideal cut.

There are many factors that vastly affect the proportions and symmetry of a diamond. If any particular part of the diamond is cut disproportionately, all of the other elements will be affected by this.

The factors that affect the proportions of a diamond are:

• Table diameter

• Total height of the stone

• Crown height

• Girdle thickness

• Angle of the pavilion and crown

• Facets to the plane of the girdle

The features that affect the symmetry of a diamond are:

• Naturals and extra facets

• Twinning, growth and grain lines

• Fringed or rough girdle, polish or burn marks

• Physical damage, breaks, cuts, chips, scratches

• The position of the table and cutlet

• The size and regularity of the facets, girdle, and cutlet