A person who breaks crystals in order to study them.
Originally used depreciatively by the mineralogist J. B. L. de Romé de l'Isle (1736–90) with reference to his rival R. J. Haüy (1743–1822) who made advances in crystallography by splitting crystals and examining their structure.
Mid 19th century; earliest use found in William Whewell (1794–1866), college head and writer on the history and philosophy of science. From crystallo- + -clast, after French cristalloclaste (J. B. L. de Romé de l'IsleCristallographie (ed. 2, 1783) I Pref. p. xxvii: see note at definition).