 The granite mountains around Chamonix have been eroded into steep needle-shaped peaks (known as ).Known locally as "protogine", these rocks are lower in the mineral biotite mica and richer in quartz than the granites commonly found elsewhere.A large part of the massif is covered by ice fields and is cut by numerous glaciers, mostly flowing northwestwards on the French side; southeastwards on the Italian side and eastwards on the Swiss side.