Diamonds take light that enters through the top and reflects it back to the eye. If all goes well on the cutting wheel, the finished stone will vary in the amount of light it reflects. However, to allow for maximum light return, a diamond must be cut perfectly with its facets acting as mirrors enabling an intricate light-relay system.
Fancy Color Diamonds
Unlike colorless diamond grading which uses simple letters, rating systems for colored diamonds are comprised of adjectives that rate stones for increasing degree of color-strength. Although grading systems for fancy color diamonds vary somewhat, most are comprised of six or so grades (in ascending order): Faint, Light, Moderate, Intense, Vivid, and Deep.
Diamonds are light prisms. Besides reflecting light, they refract it. This means they split rays into flashes of spectral light, called dispersion, which seems to flicker like fire in the stones. Stones with strong fire light up with rainbow bursts containing all the colors of the spectrum.
When moved about, well-cut diamonds sparkle like a lake spangled with sunlight or grass shimmering with dew drops. Scintillation refers to the degree of light animation a diamond exhibits.
A diamond is a house of mirrors, each of which must be cut to specific size, depending on their location, and also be aligned with adjoining mirrors. These mirrors are called “facets” and they act as relays that both reflect light as brilliance and refract it as fire. The overall care and precision with which a stone is faceted is called “polish”. Polish determines a diamond’s ability to function as a light-producer. Imagine a properly-cut diamond as a fully functioning 6-cylinder engine. If facets are misshapen or misaligned, they misfire and the engine loses functioning power. Fine polish fine tunes the diamond for peak performance ability.
When seen in light with ultraviolet (UV) rays, a significant number of diamonds—estimated to be 25-30%—emit a soft blue glow. This excitation of atoms is called “fluorescence.” Depending on its strength (GIA rates fluorescence: none, faint, medium, strong, very strong) fluorescence can mask yellowish tints in stones and “whiten” them considerably. When acute, however, fluorescence detracts from a diamond’s appearance by making it seem oily or cloudy. No one is exactly sure why some stones fluoresce and others don’t. All gemologists know is that fluorescence camouflages color because it alters the color absorption properties of the diamond. To prevent mistakes in color grading, gem labs grade diamonds in UV-free light. Since labs have already factored in fluorescence to their color grades, you need not be afraid of it in slight amounts. Indeed, a touch of blue fluorescence can make a diamond look top-white in any lighting condition with UV rays.
Today diamonds are altered using very sophisticated technologies that eliminate or reduce the visibility of inclusions. Lasers are used to create tiny tubes to reach inclusions and remove them or bleach them to make them less visible. Such diamonds are said to be “clarity-enhanced.” In addition, diamonds can be “color-enhanced” using high heat and irradiation to reduce, intensify or change completely. To prevent purchase of what are called “treated” or “enhanced” diamonds, all RockHer diamonds are subjected to thorough lab scrutiny. We sell only untreated diamonds. There is one more gemological concern that we must bring to your attention: the increasing availability of manmade, or synthetic, diamonds. These are laboratory clones of natural diamonds that require testing to be detected as such. Fortunately, gemology is keeping pace with technology and all known makes of lab-grown diamonds can be identified.