allomorphism
/ˌaləˈmɔːfɪz(ə)m/Mineralogy and Chemistry
noun
Change of crystal form without change in chemical composition; the existence or occurrence of allomorphs.
Origin
Mid 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. From allo- + -morphism. With the use in mineralogy compare paramorphism.