A rotor blade of a wind power installation with a spar cap , having a longitudinal extent (L) from a first end to a second end , a transverse extent (Q) orthogonal to the longitudinal extent (L), and a thickness (D) orthogonal to the longitudinal extent (L) and to the transverse extent (Q), wherein the first end represents the end of the spar cap , said end being disposed in the region of a root of the rotor blade and the second end represents the end of the spar cap , said end being disposed in the region of a tip of the rotor blade , - at least two tiers of a first fiber composite material , and - at least one tier of a second fiber composite material , wherein - the first fiber composite material has a matrix material and/or fibers which is/are different from that/those of the second fiber composite material; - the second fiber composite material is disposed in a portion adjacent to the second end , in the direction of the thickness (D) between the at least two tiers of the first fiber composite material; - the at least one tier of the second fiber composite material terminates ahead of the second end , wherein the fibers of the second fiber composite material comprise carbon fibers and the fibers of the first fiber composite material comprise inorganic fibers, namely electrically non-conductive fibers, wherein the number of tiers of the first fiber composite material is reduced toward the second end , wherein in the above-mentioned section adjacent to the second end containing tiers of the first and of the second fiber composite material , two external tiers of the first fiber composite material remain, in order for the tier or the tiers of the second fiber composite material to be disposed between these two external tiers of the first fiber composite material , and the second fiber composite material is surrounded by the first fiber composite material to decrease the risk of a lightning strike. the first end represents the end of the spar cap , said end being disposed in the region of a root of the rotor blade and the second end represents the end of the spar cap , said end being disposed in the region of a tip of the rotor blade , - at least two tiers of a first fiber composite material , and - at least one tier of a second fiber composite material , - at least two tiers of a first fiber composite material , and - at least one tier of a second fiber composite material , wherein - the first fiber composite material has a matrix material and/or fibers which is/are different from that/those of the second fiber composite material; - the second fiber composite material is disposed in a portion adjacent to the second end , in the direction of the thickness (D) between the at least two tiers of the first fiber composite material; - the at least one tier of the second fiber composite material terminates ahead of the second end , - the first fiber composite material has a matrix material and/or fibers which is/are different from that/those of the second fiber composite material; - the second fiber composite material is disposed in a portion adjacent to the second end , in the direction of the thickness (D) between the at least two tiers of the first fiber composite material; - the at least one tier of the second fiber composite material terminates ahead of the second end , <EOS>