The cut of a diamond gives it –fire: That is the term for the essence of its sparkle. The highly refractory properties of these precious little chunks of crystallized carbon are brought into play when a master diamond cutter begins to shape the rough diamond into a sparkling gem; the centerpiece of a piece of fine jewelry.
A diamond gathers the surrounding light. The higher the quality of light the better this stone will be able to perform its job of refracting the full spectrum of light it takes in, separated into the seven different colors that make up the visible light spectrum, blasting back out of the diamond, just the way the diamond cutter intended.
A diamond cutter controls the fire of a diamond in some very specific ways. The cleaving of a diamond, that is the initial “splitting” of the stone, done with a chisel and a wooden mallet, gives a diamond it’s largest, natural flat. This flat is the surface that a diamond cutter will begin to place other flats, i.e., facets, at angles in relation to the face.
An interesting geometrical thing about these cuts, specifically -the angle of the cut is this: A facet at around a ninety degree angle from the table will reflect the cooler end of the light spectrum: blue, green, and blue-green. Facets placed at near fortyfive degrees, will make up the red, yellow, orange, and red-orange of the fire in this ice.
A diamond’s brilliance comes from the stone itself. Diamonds have extremely high refractory properties. This crystal refracts light. This means, it bends it -and by doing so also divides it into the different wavelengths that make up different colors. This gives a diamond its fire. It only does this with the portion of light that passes through the surface of the stone. What happens to the rest of the light?
Light that is not absorbed into the transparency of the diamond and refracted is reflected. Everyone knows what that means. We’ve all seen it e.g.; water. In still water we can see our reflection, and at the same time, see through the water to the bottom. This light that is reflected off the surfaces of a cut diamond is what gives it brilliance.
To summarize:
Refracted Light: Fire
Reflected Light: Brilliance
To get all scientific: The refractory properties of a material can be measured. The speed of light is slowed as it passes through different transparent materials e.g. air (gas) water, ice, glass, quartz and so on. It is slowed most of all as it passes through a diamond, getting a score of 2.41 on the refractive index. A cubic Zirconia would have a 2.2 at the most. Water is at 1.33, and air; 1.0003. Space is 1.0. When light is refracted, slowed down, it bends and separates into the different colors of the light spectrum. These light waves are then reflected off the inside of the diamond’s lower facets and projected out of the stone to the -eye of the beholder. Any of these tiny little rainbows reflected back to the eye, will be so tiny that they will appear to be sparkling little flashes of white light. The beams that pass over your shoulder onto the wall will be projected as rainbows, separated into hot and cold color groups.
