Cut refers to the angles and proportions a skilled craftsman creates in transforming a rough diamond into a polished diamond.
A well-cut diamond will reflect light internally from one mirror-like facet to another, dispersing it through the top of the stone. Cuts that are too deep or too shallow lose or leak light through the side or bottom, affecting the diamond's brilliance.
Cut is the only one of the 4C's that is influenced by the human hand. The rest (color, clarity, and carat) are created naturally as diamonds form in the earth.
Diamond cutting requires great skill and training. The cutter must polish tiny surfaces known as facets onto the rough diamond. This process is what creates the facets known as the crown, culet, table, girdle and pavilion of the diamond.
The facets, when arranged in precise proportions, will maximize the fire life and brilliance of a diamond. To cut a diamond perfectly, a craftsman will often need to cut away more than 50% of the rough diamond.
Cutting style is categorized into three basic types, which differ in the facets of each style:
- Step-cut have rows of facets that resemble the steps of a staircase. The emerald and baguette are examples of this cutting style.
- Brilliant-cut scientifically found to reflect the most light
- Mixed-cut have both step and brilliant-cut facets. One of the most popular types of mixed-cuts is the Princess.
The Millennium Star, weighing 777 carats in the rough, was polished down to 203 carats in order to maximize its beauty.
