出典:Wiktionary
出典:『Wiktionary』 (2026/05/13 00:44 UTC 版)
pheno- + -cryst
phenocryst (plural phenocrysts)
出典:Wikipedia
出典:『Wikipedia』 (2011/05/15 16:00 UTC 版)
A phenocryst is a relatively large and usually conspicuous crystal distinctly larger than the grains of the rock groundmass of a porphyritic igneous rock. Phenocrysts often have euhedral forms either due to early growth within a magma or by post-emplacement recrystallization.