Designing the Modern Cut Diamond 5.03

Designing the Modern Cut Diamond 5.03

Designing the Modern Cut

Transmitted light does enter the diamond.


Reflected light does not enter the diamond.

The concept of designing the modern brilliant cut was to formulate an optimum angle, depth and table percentage relationship. The properties that had to be understood to accomplish this task included both transmitted light and reflected light. “Transmitted light” is what enters the diamond and reflected light is what bounces from the surfaces of the diamond.

Diamond’s Refractive Index | Light Travel Inside Diamond

 Different gems or substances have varying refractive indexes. Diamond’s is unique in the sense that it has the high refractive index of 2.417. Cubic zirconia’s is about 2.15. The higher the RI (refractive index) the more ability it has to bend light. Light bends because the specific material structure slows it down as it enters. We see this in the dislocated image of an object immersed in a liquid, such as the apparent bending of a straw sitting in a glass of water. In vacuum conditions (such as interstellar space), light travels at approximately 186,000 miles per second, with an effective refractive index of 1. Once light hits our atmosphere, it slows down slightly due to a refractive index of 1.00029. Through diamond, light travels at closely 77,000 miles per second (186,000/2.417).

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