monchiquite Petrogr.
(mɒnˈtʃiːkwaɪt)
[a. G. monchiquite (Hunter & Rosenbusch 1890, in Tschermak's mineral. u. petrograph. Mittheilungen XI. 447), f. Serra de Monchique, name of a mountain range in southern Portugal where such a rock is found: see -ite1.]
A lamprophyre containing small phenocrysts of olivine and augite, and usu. also biotite or an amphibole, in a glassy ground-mass consisting of or containing analcite.
| 1891 Ann. Rep. Arkansas Geol. Survey 1890 II. iv. 110 The Brazilian dikes..form an olivine-free class of the rock that Rosenbusch calls monchiquite. 1896 Jrnl. Geol. IV. 679 (heading) On the monchiquites or analcite group of igneous rocks. 1961 [see camptonite]. 1965 [see ferroan a.]. |