外来晶(Xenocrystals),亦称捕虏晶,在火成岩中为外岩浆矿物.虽在各种有关的教科书及一些著述中早有提及,但多不详.但外来晶对于正确确定岩浆岩类型,特别是对于了解深部地质信息和寻找深源包体矿床等,有着极为重要的意义.笔者近年来较多地接触到这一问题,并作了一些初步的研究工作,愿意提出来与大家探讨,以期引起有关工作者的重视. Xenocrystals, also known as xenocrysts, are extramagnetic minerals in igneous rocks, although they are not mentioned in many texts and descriptions of some kinds of texts, however, extraneous crystals are of great importance for the correct determination of magmatic rock types, Especially for understanding deep geological information and searching for deep-sourced ore bodies, etc. The author has come into more contact with this issue in recent years and has made some initial research work and is willing to discuss with you, With a view to arousing the attention of the workers concerned.