Granitoid orthogneiss with homogeneous medium grain and dark gray color due to the presence of a significant quantity of biotite mica; it is the darkest of the serizzo varieties. Very evident foliation. Mineralogical composition: abundant quartz, potassium feldspar in small porphyroclasts, plagioclase (An 25-30%), biotite, scarce muscovite, ± epidote (allanite).
Location of extraction:
Baceno, Crodo, Premia
Geological relevance:
Antigorio nappe (Lower Pennidic)
