LIGHT SERIZZO FORMAZZA

Light gray, granitoid, ortoderived gneiss with a medium-fine grain highlighted by light and uniform feldspar lenses.
The schistose texture is little evident due to both the weak iso-orientation of the feldspars and the modest presence of "biotite" dark and "muscovite" light mica, which can be recognised under a macroscope only.
The micas (fillo silicates) do not generate any clear differentiation among different mica/quartz-feldspar mineralogical levels, which are typical of gneissic rocks instead (high-rate metamorphic layering). Therefore, the rock preserves its granitoid aspect (ortogneiss).
The above mentioned petrographic features give a light background to the macroscopic scale, as well as a uniform design highlighted by the medium-fine grain of the feldspar and quartz lenses and by the absence of any clear and pervasive schistosity planes.
The optical effect, which can be defined as "spot-like", is peculiar and unmistakable, and is provided by a widespread scattering of the tiny dark stains produced by biotite concentration, which sometimes returns, on a larger scale, as the effect of widespread femic inclusions parallel to the light schistose texture.