Ferrisanidine

ferrisanidine

johillerite

axelite

badalovite

Images

Formula: K(Fe3+Si3O8)
Tectosilicate (framework silicate), alkali feldspar subgroup, feldspar group
Crystal System: Monoclinic
Specific gravity: 2.722 calculated
Streak: White
Colour: Colourless to white
Environments

Fumeroles

Ferrisanidine is a relatively new mineral, approved in 2019.

Localities

At the type locality, the Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia, the temperature measured in the area during the collecting of samples with ferrisanidine was ~400°C. It is noteworthy that the sublimates of the Arsenatnaya fumarole contain rich silicate mineralisation including feldspars. Sanidinefilatovite, anorthoclase and plagioclase (from andesine to anorthite) are quite common here. Ferrisanidine is the rarest feldspar in this fumarole. It is associated with aegirine, cassiterite, hematite, sylvite, halite, johillerite, badalovite, arsmirandite, axelite, aphthitalite, litidionite, tridymite, polyarsite and evseevite (Minerals 9.12.770).
Ferrisanidine from the Arsenatnaya fumarole - Image

At the Leucite Hills Mining District, Sweetwater County, Wyoming, USA, ferrisanidine has been found in lamproite (HOM).

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