The energy spectra of abundant heavy nuclei from carbon to iron collected by the NUCLEON space experiment after two years of operation are presented. The spectra were measured with use of both calorimeter and KLEM methods. The complex behavior of the spectra from carbon to silicon in the energy range from a few TeV to hundreds of TeV per particle is presented and discussed. The difference between the spectrum of iron and the spectra of other heavy nuclei from carbon to silicon and a signature of a universal break in the spectra of all nuclei near the magnetic rigidity 10 TV are emphasized. Some new features in the spectra of heavy nuclei are discussed.