Observation point: by the path over Pian del Lupo 
 
On your left side, you can see Sissone river carved his valley into a great variety of rocks.  
In the lower part, you can see steep slopes, covered by sparse coniferous woods; anphibolitic dark green rocks outcrop here and there, giving rise to trackless cliffs. This rocks were originated during Jurassic period on an oceanic seafloor, as basaltic lavas, and were deformed, metamophosed and finally exhumed during alpine orogeny. Basaltic oceanic crust rocks are tipical of this part of Val Malenco: you'll see them in detail on the path to Muretto Pass. 
On the top, Sissone valley opens in a wide glacial basin, closed by the majestic massif of Monte Disgrazia. In Italian, "disgrazia" means an accident or a disaster, but this isn't the origin of the name: it comes from vernacular "desglàcia", that is to thaw, referred to the front of the glacier hanging on the valley, and to ice blocks falling down from there. 
The upper part of the valley is cut into Màsino-Bregaglia batholith, a complex intrusive granodioritic and quarzodioritic body, emplaced during tertiary orogenetic phases. The contact between the hot magma and the surrounding rocks ia at the origin of peculiar metamorphic lithotypes, sometimes with very rare or also unique minerals.  The boulders carried down by the glacier during the Little Ice Age are often made of this kinds of contact metamorphic rocks, so Sissone valley is famous among mineral collectors, although beautifull crystals are now rather hard to find.