The 4 C’s of Diamonds

Part I - The Cut

Diamonds are cut in many fancy shapes: marquises, baguettes, hearts, pears, ovals and square or emerald cuts. However the classic is the round brilliant. This style of cut has enjoyed a long and intense development throughout its history, which began as early as the first century BC, and in the 20th century reaching its zenith in the form of a circular brilliant cut, which is a standardised style of cut.

Perfectly Cut Diamond


Uncut diamonds give no hint of the unique optical properties of cut stones. Rough diamonds hide their beauty beneath a yellow, brown or grey tinted “coat”, a non- transparent skin which covers many rough stones. Only cutting can transform the diamond rough into  a crystal clear stone which, in terms of clarity and lustre and with a magical scattering of prismatic colours, surpasses all other precious stones and has fascinated men for centuries.
The beauty of a cut diamond is revealed not only in an appealing body colour which is generally the first feature which attracts the eye but also in its superlative optical properties, particularly its high refractive index and and colour dispersion. Maximum brilliance – the combination of proportion, lustre, light refraction, total reflection, colour dispersion and scintillation is the result of practical experience and the craftsmanship of a master diamond cutter, and also of the knowledge and application of the physio-optical laws that govern the development of an optimum cut.
In 1919 Marcel Tolkowsky developed the ideal proportions of the round brilliant cut which mathematically maximised brilliance and dispersion in a diamond.
The round brilliant cut has 58 facets arrived at after a study of the stone to determine the best way to achieve maximum yield from it before the processes of cleaving, sawing, bruting and putting on the facets.
The cut of a diamond refers to the make and proportions of a stone. When a diamond is cut to good proportions light is reflected from one facet to another and dispersed through the top of the stone. If the cut is too deep, some light will escape through the opposite side of the pavilion. If the cut is too shallow light escapes through the pavilion before it can be reflected.
Polish refers to the quality of a diamond’s surface condition after the cutting process and symmetry refers to the symmetrical arrangement of the facets. Excellent make, polish and symmetry are desirable and each of these factors influences the price.