Noun
Alum.
Source: Webster's dictionaryNative alumen from Melos appears to have been a mixture mainly of alunogen ( Almain (SOmain )main ·17H 2 O ) with alum and other minor sulfates. Source: Internet
The alumen of the ancients then, was not always the same as the alum of the moderns. Source: Internet
Pliny describes several other species of alumen but it is not clear as to what these minerals are. Source: Internet
Pliny informs us that 'alumen' was found naturally in the earth. Source: Internet