Diamond type
Diamond type is a method of scientifically classifying diamonds by the level and type of their chemical impurities. Diamonds are separated into four types: Type Ia, Type Ib, Type IIa, and Type IIb. The impurities measured are at the atomic level within the crystal lattice of carbon atoms and so, unlike inclusions, require an infrared spectrometer to detect.
Red diamond
The color in red diamonds is assessed according to its hue and saturation. Red diamonds can occur with secondary colors, such as brown-red, orange-red, or purple-red, but red is not a modifying color for any other diamond color. Additionally, red diamonds never appear with a tertiary modifying color, as is the case in other diamond colors. A pure red diamond is ideal but an even rarer find than a red with a secondary color. Like with other diamond colors, a purely red diamond will fetch a higher per carat price than one with a secondary hue. Brownish red and Orangey red diamonds are generally considered inferior to Purplish Red diamonds and are priced accordingly. All of these colors run upwards of $400,000 per carat, but a pure red diamond can cost significantly more per carat. Few colors of fancy color diamonds are characterized by having a singular color intensity. This phenomenon only exists with three colors: black diamonds, white diamonds, and red diamonds. Since the source of the red in red diamonds is considered to be a hyper-concentrated occurrence of pink, this would actually make red the darkest shade of pink possible, which is why it is only able to appear in one intensity. Red diamonds will only be graded Fancy Red, Fancy Brownish Red, Fancy Purplish Red, or Fancy Orangey Red. An easy way to tell whether a red diamond is fake is if the seller is offering it with an intensity grade like other diamond colors (Fancy Light, Fancy Intense, Fancy Vivid etc.). There are so few red diamonds that the GIA records show that over a 30 year period from 1957–1987, not a single GIA lab report with the term “red” was issued. Some diamond polishers have achieved a GIA grading of Fancy Red for a diamond by re-polishing a Fancy Deep Pink diamond, although this is very hard to accomplish and has only been successfully completed less than a handful of times.