Minerals described in 1821

Aegirine is a mineral. It is a member of the clinopyroxene group of inosilicate minerals. Acmite is a fibrous green-colored variety of aegirine, with the name also used as a synonym. It was first described in 1821, in Kongsberg, Norway.

Blödite or bloedite is a hydrated sodium magnesium sulfate mineral with the formula Na2Mg(SO4)2·4H2O. The mineral is clear to yellow in color often darkened by inclusions and forms monoclinic crystals.

Humboldtine is a rarely occurring mineral from the mineral class of "organic compounds" with the chemical composition FeC2O4•2H2O and is therefore a water-containing iron(II) oxalate or the iron salt of oxalic acid.