Thermessaite-(NH4)
Thermessaite-(NH4) is an IMA-recognized mineral species in the sulfate class, with the chemical formula (NH₄)₂AlF₃(SO₄).
It crystallizes in the orthorhombic crystal system (space group Pbcn). It is a member of the Thermessaite structural group.
Key properties: Mohs hardness 2.185; specific gravity 2.185; White streak; Vitreous luster.
IMA symbol Tms-NH4, IMA status: approved, named in 2011.
Fumarole sublimate encrustation at the rim of an active volcanic crater.
It is found associated with Thermessaite, sulfur, arcanite, mascagnite, intermediate members of the arcanite- mascagnite series.
Prefix identifies the (NH4)-analogue of thermessaite.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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