Definition of alum
i. Any hydrous, alkali aluminum sulfate mineral, including kalinite, potassium alum, sodium alum, mendozite, tschermigite, and lonecreekite.
Synonym of: Kalinite
ii. A former name for kalinite and potassium alum.
iii. Any salts that are double sulfates of aluminum, chromium, iron, or manganese and one of the alkali metals.
Synonym of: Kalinite
ii. A former name for kalinite and potassium alum.
iii. Any salts that are double sulfates of aluminum, chromium, iron, or manganese and one of the alkali metals.