petrostearin--prophetes.ai

petrostearin
  (pɛtrəʊˈstiːərɪn)
  [f. petro-¹ + stearin.]
  A name for ozocerite, a mineral resembling stearin.

1879 Webster, Suppl., Petro-stearine.., a solid unctuous material of which certain kinds of candles are made. 1893 in Syd. Soc. Lex.

Oxford English Dictionary