Cervantite is an antimony oxide mineral with formula Sb3+Sb5+O4 (antimony tetroxide). It was first described in 1850 for an occurrence in Cervantes, Galicia, Spain, and named for the locality. The mineral was questioned and disapproved, but re-approved and verified in 1962 based on material from the Zajaca-Stolice district, Brasina, Serbia. It occurs as a secondary alteration product of antimony bearing minerals, mainly stibnite.