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.
Diamond clarity
The diamond industry uses the term "internal characteristics" instead of "inclusions". For natural diamonds, the "internal characteristics" in the diamond are growth crystals that give the diamond its character and unique fingerprint. When diamonds are graded, they are magnified at 10x power.In 1952, Richard T. Liddicoat, along with Marquis Person, Joe Phillips, Robert Crowningshield and Bert Krashes began to work on a new diamond grading system which they called the "diamond grading and evaluation appraisal". In 1953, they released their new system which assessed three aspects of diamonds; make, color and clarity. They took terminology used in the industry at the time and refined the definitions to produce a clarity scale by which diamonds could be consistently graded. The system at that time contained nine grades: Flawless, VVS, VVS, VS, VS, SI, SI, I, and I. The 'I' of the I, and I grades originally stood for "Imperfect".