Assertion: biotite | /r/AtLocation | igneous rocks
Facets:
Source sentences:
text: Biotite and amphibole do occur together in igneous rocks, but the association is not all that common.
text: The more important occurrences follow: Biotite occurs in many igneous rocks (e.g., granites and granodiorites), is common in many pegmatite masses, and constitutes one of the chief components of many metamorphic rocks (e.g., gneisses, schists, and hornfelses).