The Department of GeologicalS ciences, University of California, has received some very good specimens of the rare mineral voltaite from Jerome, Arizona, sent by Mr. George L. Mclntyre of Eureka, Utah. He reported that the specimens were formed in brecciated quattz immediately above burning sulphide ore on the upper levels of the United Verde Mine. It is his opinion that the voltaite has been formed by the ascending sulphur vapors. The ore of the mine has been burning for a number of years; it was first set on fire when the back of a stope collapsed and the friction ignited the sulphur present in the sulphides. Reber1 reported the burning sulphide ore in his report on the region, but he made no mention of the voltaite. This article was prepared under the direction of Professor Arthur S. Eakle and the writer wishes to gratefully acknowledge his aid and helpful criticism.