phenocryst

As nouns the difference between porphyry and phenocryst

is that porphyry is a hard igneous rock consisting of large crystals in a fine-grained matrix while phenocryst is any relatively large crystal embedded in a more fine-grained or glassy igneous rock.

As a noun phenocryst is

(mineralogy) any relatively large crystal embedded in a more fine-grained or glassy igneous rock.

As nouns the difference between xenocryst and phenocryst

is that xenocryst is a crystal that does not occur in a specific igneous rock while phenocryst is any relatively large crystal embedded in a more fine-grained or glassy igneous rock.

As nouns the difference between taxonomy and phenocryst

is that taxonomy is the science or the technique used to make a classification while phenocryst is (mineralogy) any relatively large crystal embedded in a more fine-grained or glassy igneous rock.

As nouns the difference between xenolith and phenocryst

is that xenolith is any piece of rock having a different origin to that of the igneous rock in which it is found while phenocryst is any relatively large crystal embedded in a more fine-grained or glassy igneous rock.

Macrocryst is a related term of phenocryst.

In mineralogy terms the difference between phenocryst and macrocryst

is that phenocryst is any relatively large crystal embedded in a more fine-grained or glassy igneous rock while macrocryst is a relatively large crystal occurring in a mineral deposit, usually defined as one between 0.5 mm and 10 mm in size.