Ferrisepiolite
Ferrisepiolite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Fe³⁺,Fe²⁺,Mg)₄[(Si,Fe³⁺)₆O₁₅](O,OH)₂·6H₂O.
It crystallizes in the orthorhombic crystal system (space group Pncn). It is a member of the Sepiolite structural group.
Key properties: Mohs hardness 2–2.5; specific gravity 2.51; Brown streak; Non-metallic luster.
IMA symbol Fsep, IMA status: approved, named in 2010.
Found in late-stage veinlets cutting copper-sulfide ores hosted in layered hedenbergite- andradite-actinolite-vesuvianite contact metamorphic rocks (skarns).
It is found associated with Calcite, siderite.
As the Fe3+-dominant analog of sepiolite.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
Browse more F minerals or help write this entry.