HAUY, RENÉ-JUST. - Priest, born at St-Just (Oise) on 28 Feb. 1743, died in Paris on 3 June 1822. A distinguished crystallographer and mineralogist, he is to be regarded as one of the founders of crystallography.
Educated at the Collège de Navarre, where he later became a professor, he embraced the ecclesiastical career there. At first he concerned himself with the natural sciences in general, but after being introduced to mineralogy by the mineralogist Daubenton, he devoted himself entirely to that science. From 1783 he was a member of the Academy of Sciences. In 1794 he was appointed curator of the Museum of Mines, and in 1802 became professor of mineralogy at the Museum, succeeding Dolomieu. Finally, he was professor of mineralogy at the University of Paris from its foundation.
He owes his fame to the fundamental law of rational truncations, or of rational indices, which he discovered and which bears his name, and to his theory on the structure of crystals published in 1783 (v. CRISTALLO).
A man of rare virtue, even amidst the highest honours he remained a modest and pious priest, scrupulously observant of the smallest religious duties (Cuvier).