Arrojadite-(KNa)
Arrojadite-(KNa) is an IMA-recognized mineral species in the phosphate class, with the chemical formula KNa₃(CaNa₂)Fe²⁺₁₃Al(PO₄)₁₁(PO₃OH)(OH)₂.
It crystallizes in the monoclinic crystal system (space group Cc). It is a member of the Arrojadite structural group.
Key properties: Mohs hardness 5; specific gravity 3.527; Vitreous to greasy luster; optically biaxial.
IMA symbol Ajd-KNa, IMA status: approved, named in 2005.
A high-temperature (≈ 800 ° C) primary mineral in granite pegmatites.
It is found associated with Graftonite, cassiterite, spodumene, beryl, muscovite (Nickel Plate mine, South Dakota, USA).
The mineral was named to honor Miguel Arrojado Ribeiro Lisbôa (1872–1932), Brazilian geologist.
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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