Gems Geometry: From Raw Structure to Precious Stone

This paper introduces some considerations regarding the geometric principles that lead the configuration of precious gems. Geometry crosses and characterises different aspects of precious gems: from the atomic composition of its raw structure, to the classification of the crystalline system, up to defining shapes and configurations of possible cuts, as well as to control the functioning of the instruments that allow its execution. From age to age, geometry is leading the lapidary art that bases its foundations and rules on it, mainly in order to cut and manufacture the stones, and also to identify the rules that could enhance the brightness or minimize the wastefulness of precious material during the processing. Starting from research still in progress by the authors, this paper will outline the role of geometry in the fields of crystallographic classification, the cuts classification, the methods for design and execution, also through the conspicuous iconography and the digital modelling.