The Collaborative International Dictionary of English v.0.48:

massicot \mas"si*cot\, n. [F. massicot; E. masticot is a
   corruption.] (Chem.)
   Lead monoxide (also called Lead protoxide), PbO, obtained
   as a yellow amorphous powder, the fused and crystalline form
   of which is called litharge; lead ocher. It is used as a
   pigment. It is also called lead oxide yellow, as opposed to
   red lead, which is lead tetroxide Pb3O4.
   [1913 Webster +PJC]

   Note: Massicot is sometimes used by painters, and also as a
         drier in the composition of ointments and plasters.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

minium \min"i*um\ (?; 277), n. [L. minium, an Iberian word, the
   Romans getting all their cinnabar from Spain; cf. Basque
   armine['a].] (Chem.)
   A heavy, brilliant red pigment, consisting of an oxide of
   lead, Pb3O4, obtained by exposing lead or massicot to a
   gentle and continued heat in the air. It is used as a cement,
   as a paint, and in the manufacture of flint glass. Called
   also red lead, lead tetroxide, lead orthoplumbate,
   mineral orange, mineral red, Paris red, Saturn red,
   and less definitively, lead oxide.
   [1913 Webster]