(geology) A common and widely-distributed metamorphic rock having bands or veins, but not schistose.

plural of gneiss

(geology) Having properties similar to gneiss.

(geology) of or relating to gneiss

(geology) Having a structure similar to that of gneiss, or intermediate between that of gneiss and mica or granite

(geology) A metamorphic rock having the composition of a laminated granite

plural of gneissoid

(geology) granitic gneiss

Resembling or containing gneiss.