phenocryst

[ fee-nuh-krist, fen-uh- ]
/ ˈfi nə krɪst, ˈfɛn ə- /

noun Petrology.

any of the conspicuous crystals in a porphyritic rock.

Origin of phenocryst

First recorded in 1890–95; pheno- + cryst(al)

Words nearby phenocryst

phenmetrazine, pheno-, phenobarbital, phenobarbitone, phenocopy, phenocryst, phenodeviant, phenogram, phenol, phenol coefficient, phenol red

British Dictionary definitions for phenocryst

phenocryst
/ (ˈfiːnəˌkrɪst, ˈfɛn-) /

noun

any of several large crystals that are embedded in a mass of smaller crystals in igneous rocks such as porphyry

Word Origin for phenocryst

C19: from pheno- (shining) + crystal

Scientific definitions for phenocryst

phenocryst
[ fē′nə-krĭst′ ]

A large crystal that is surrounded by a finer-grained matrix in an igneous rock. Phenocrysts are usually the first crystals to form from a cooling magma, and therefore have sufficient room to grow to a large size. They are analogous to porphyroblasts in metamorphic rock.