gems, corundum, history.1, chemistry.2, mineralogy, crystallography

A concise practical introduction to crystallography based on the system of Jean-Baptiste Louis de Romé de l’Isle. Published in Paris in 1792, the work abridges Romé de l’Isle’s much larger Cristallographie (1783) and presents a simplified method for recognising and distinguishing the crystal forms of minerals in a collection. It was intended for use with a collection of polyhedral models, which served as three-dimensional representations of the forms described in the text. The manual was designed particularly for mineral collectors, providing an accessible means of identifying and arranging specimens according to their crystallisation. It thus served both as an elementary guide to Romé de l’Isle’s crystallographic system and as an explanation of the accompanying crystal models.