Definition of "litharge"

Yes: living among the cohabations[sic] of Faust himself, among the litharge and agate and hyacinth and pearls.

1947, Malcolm Lowry, Under the Volcano, New York: Reynal & Hitchcock, page 86

From an inner pocket he produces a costly Ramillies Wig, shakes it out in a brisk Cloud of scented Litharge, and claps it on, with a minimum of fuss, over his ascetic’s Crop.

1997, Thomas Pynchon, Mason & Dixon, 1st US edition, New York: Henry Holt and Company, part One: Latitudes and Departures, page 227