phenocryst

Alternative definitions (0), class: vernacular (0)
Term: phenocryst
Definition:

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. [Wikipedia]

Created 2023.04.16
Last Modified 2023.04.16
Contributed by Ryan McGranaghan
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