:Outstanding acicular yellow crystals of the extremely rare mineral magnanelliite from the type and only known locality worldwide: Monte Arsiccio Mine, Apuan Alps, Tuscany, Italy. Magnanelliite has been named after the well known mineral collector and mineralogist Dr.Stefano Magnanelli, protagonist of exceptional finds in Monte Arsiccio mine and other parts of Tuscany. Magnanelliite is a Fe-K sulphate and it is the Fe+analogue of alcaparrosaite. — Photo: David Hospital · CC BY-SA 4.0
Magnanelliite
Magnanelliite is an IMA-recognized mineral species in the sulfate class, with the chemical formula K₃Fe³⁺₂(SO₄)₄(OH)(H₂O)₂.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Alcaparrosaite structural group.
Key properties: Mohs hardness 3; specific gravity 2.82; Pale yellow streak; Vitreous luster; optically biaxial.
IMA symbol Mgn, IMA status: approved, named in 2019.
Secondary in an oxidized baryte-pyrite-magnetite-hematite deposit in K-bearing rocks.
It is found associated with Alum-(K), giacovazzoite, gypsum, jarosite, krausite, melanterite, scordariite.
The mineral was named to honor Stefano Magnanelli (b. 1959), chemist and mineral collector, for contributions to the mineralogy of the hydrothermal veins of the Apuan Alps.