The composition of the carbonaceous matter of dusky apatites was studied from the Variscan granitoids of the Tribec and Mala Fatra Mts. crystalline cores. Dark-coloured pigment in the apatite of the Tribec Mts. biotite tonalite contains 45.3 wt. % of graphite, 45.3 wt. % of hydrocarbons, and 9.4 wt. % of carbide. The apatite from the Mala Fatra granodiorite contains 24.1 wt. % of graphite, 61.6 wt. % of hydrocarbons, 8.7 wt. % of carbide and 5.6 wt. % of carbonates. Carbon-bearing dusky apatite originated by the assimilation of graphite-bearing crystalline schists by granitoid melts. The presence of dusky apatite indicates reducing conditions in these melts.