idiomorphic

adjective

id·​i·​o·​mor·​phic ˌi-dē-ə-ˈmȯr-fik 

: having the proper form or shape

—used of minerals whose crystalline growth has not been interfered with

Word History

Etymology

Greek idiomorphos, from idio- + -morphos -morphous

First Known Use

1887, in the meaning defined above