Explores an exceptional family of diamonds, referred to as “CLIPPIR” (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular and Resorbed), that formed in a super-deep environment.
Read MoreThis article discusses the history and ongoing development of GIA's colour grading system, and explains how its laboratory applies it.
Read MoreHigh-quality CVD-grown diamonds, comparable in colour and clarity to natural diamonds, can be identified using a combination of gemmological and spectroscopic properties.
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This article reviews the GIA Laboratory’s history of reporting on certain types of graining which are often the only characteristics present in large, high-clarity, high-colour diamonds.
Read MoreThe GIA diamond cut grading system described here includes the components of brightness, fire, scintillation, polish and symmetry, as well as weight and durability concerns, into a single overall grade for cut quality for standard round brilliants.
Read MoreThis second major article in a three-dimensional modelling study analyses fire – the visible extent of light dispersed into spectral colours.
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This article explores and identifies the changes that type IIa GE POL diamonds experience before and after HPHT annealing.
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Results from spectroscopic analyses of GE POL high-pressure high-temperature (HPHT) annealed nominally type IIa diamonds are presented, and these spectral characteristics are compared with those of untreated diamonds of similar appearance and type.
Read MoreGeneral Electric has developed a variety of high-temperature annealing techniques at different pressures for enhancing the optical properties of polycrystalline synthetic diamond films and single-crystal synthetic diamond.
Read MoreThis article reports on the study of six diamonds, both before and after a filling treatment, and the examination of 12 additional filled stones.
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