Home > American Minerals IV – August 26 > MS1636 Alunite

Alunite - Sold

Alunite is a potassium aluminum sulfate hydroxide. Alunite was the first discovered species of a rather common structure type, itself becoming namesake for an entire supergroup (Bayliss et al., 2010). While known since the 15th century, it was professor François Sulpice Beudant (1787-1850) who assigned this mineral its currently accepted name in his 1824 Traité Élémentaire de Minéralogie. Butler & Gale (1912) first described this American occurrence.

Alunite here forms a pseudo-octahedral crystal, somewhat skeletal in development, measuring 2.4 by 1.9 cm. The main crystal is sharp with limpid corners; smaller crystals are also attached. Large crystal size for the species. This specimen was part of the Charles Trantham (1936-2020) estate.