HAUY, Rene-Just (1743-1822). Traite de Mineralogie. Paris: Louis, 1801.

4 volumes text, 8vo (216 x 140 mm); and atlas, oblong 4to (241 x 305 mm). Half-titles; 86 engraved plates. (A few pink stains to some plates from original paste-paper binding, others slightly dampstained, atlas title-page torn at lower corner margin.) Text volumes: Original pink paste-paper wrappers, printed spine labels, uncut (losses to spine panels and some chipping to labels, some separation to covers); morocco-backed folding cases. Atlas volume: Contemporary blue paste-paper boards (rebacked in calf, extremities rubbed).

FIRST EDITION, signed by the publisher beneath the "Extrait du Decret concernant les Contrefacteurs" on the verso of the half-title in volume one. Hauy's main and most influential work in which he presents his discovery of the geometrical law of crystallization and of piezo-electricity. Hauy developed the theory that minerals are composed of regularly arranged elementary particles, which he termed "integrating molecules." His work was crucial for understanding crystal symmetry and the optical properties of crystals, and would lay the groundwork for their classification. ONE OF THE MOST INFLUENTIAL WORKS WRITTEN IN MINERALOGY AND CRYSTALLOGRAPHY. DSB, VI, p. 179; Hoover 391; Schuh 2122; Ward & Carozzi 1021-1022.