From Steno to Haüy: early crystallography and the global history of mineral classification

The intellectual foundations of geology are inseparable from advances in mineralogy and crystallography. This study reviews the transition from descriptive mineral catalogues to quantitative science, emphasizing Nicolas Steno’s seventeenth-century law of constancy of interfacial angles and René-Just Haüy’s crystallographic theory articulated in Traité de Minéralogie (1801). These milestones established mineralogy as a rigorous discipline and provided the structural basis for modern crystallography. Parallel debates in Europe, particularly Werner’s Neptunism and Hutton’s Plutonism, framed competing models of rock genesis and shaped the emergence of petrology. Beyond Europe, comparative perspectives highlight Chinese materia medica, Indian gemological and metallurgical treatises, and Islamic alchemical traditions, which independently classified minerals and advanced experimental techniques. Synthesizing these contributions reveals mineralogy as a global scientific enterprise that connected natural philosophy, chemistry, and geology. This historical analysis demonstrates how crystallography and mineral classification formed the cornerstone of modern geoscience and materials research.