Alunite occurs as veins and replacement masses in trachyte, rhyolite, and similar potassium rich volcanic rocks.

It is formed by the action of sulfuric acid bearing solutions on these rocks during the oxidation and leaching of metal sulfide deposits.

[8] Historically extensive deposits were mined in Tuscany and Hungary, and at Bulahdelah, New South Wales, Australia.

In the United States it is found in the San Juan district of Colorado; Goldfield, Nevada; the ghost town of Alunite, Utah near Marysvale; and Red Mountain near Patagonia, Arizona.

An article in the May/June 2019 issue of Archaeology magazine states that in China, in Henan province, an assortment of ceramic objects and jars were found, dating back 2000 years.