Lewis Short
(adjective) : pūmĭcĕus, a, um, pumex
* Of pumice-stone, or of soft stone; in gen. (very rare): molae,Ov. F. 6, 318: sedes,Sil. 7, 419: antra,Stat. S. 3, 1, 144; cf. fontes,flowing from pumice-stone,Mart. 4, 57, 2.
* Trop.: oculi,not in a condition to weep, stony, dry,Plaut. Ps. 1, 1, 73.
Charlton T. Lewis, Charles Short, A Latin Dictionary