Diamonds can be cut into many different shapes. The person responsible for polishing a diamond is called a cutter, who is responsible for making the diamond look the way it does. This proficient individual uses dust from a diamond on a special polishing wheel to cut a new diamond. These cuts are flat surfaces called diamond facets. Because the cutter has to think about symmetry, length, depth and height of each facet, it is a highly regarded skill in the jewellery industry.
Facets are the surfaces of a diamond that are polished. These facets can then refract the light within the diamond and give off the spectrum of beautiful colours. In the jewellery world, this is known as the fire, sparkle or luster of the diamond.
Because every facet has the potential to change a light ray’s plane of travel, every facet must be considered in any complete calculation of light paths. Just as a two-dimensional slice of a diamond provides incomplete information about the three-dimensional nature of light behavior inside a diamond, this two-dimensional slice also provides incomplete information about light behavior outside the diamond. A diamond’s panorama is three-dimensional. Although diamonds are highly symmetrical, light can enter a diamond from many directions and many angles.