corundum, history.1, chemistry.2, properties.3, gems

An early crystallographic study by Jacques-Louis, Comte de Bournon, devoted to corundum specimens from the East Indies and China. Bournon describes the principal crystal forms and their modifications, using geometrical relationships to characterize the mineral more precisely. The paper was closely associated with contemporary work by Charles Francis Greville on corundum and helped establish crystallography as an important means of distinguishing corundum from other hard stones then confused with it. Of particular gemological significance, the study contributed to the scientific recognition of corundum as the mineral species that includes ruby and sapphire.