Describes the phenomenon of pleochroism and its complex effect on the appearance of coloured stones.
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How contrast patterns can increase perceived brightness and optimise a gemstone's appearance.
Read MoreA presentation of parameters used to support GIA's symmetry grading system.
Read MoreA recent study compares a specially created model of the Hope diamond with recent computer models of the French Blue to determine if other stones could have resulted from either recutting.
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This study uses both historical information and modern data to create a computer model of the Tavernier Blue, orienting the finished diamond within the original diamond crystal.
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With the use of modern tools and technology, this article sheds light on the history and provenance of both the French Blue and the Hope diamonds.
Read MoreThis article discusses the history and ongoing development of GIA's colour grading system, and explains how its laboratory applies it.
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.
Read MoreA mathematical model which can analyse how appearance factors depend on proportions.
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