Dust and the far-UV spectral energy distribution of quasars
  The spectral energy distribution of quasars shows a sharp steepening of the continuum shortward of ~ 1100 A. We present a new dust extinction model consisting of crystalline carbon grains. We analyze the unusual extinction properties of this dust and proceed to show how the observed UV spectral break can be successfully modelled by crystalline carbon dust. 
Luc Binette, Yair Krongold, Gladis Magris Crestini and Jose Antonio de   Diego