Koenenite
Koenenite is an IMA-recognized mineral species in the halide class, with the chemical formula Na₄Mg₉Al₄Cl₁₂(OH)₂₂.
It crystallizes in the hexagonal crystal system (space group R-3m).
Key properties: Mohs hardness 1.5–2; specific gravity 1.82–2.08; Pearly on cleavage surfaces luster; optically uniaxial.
IMA symbol Koe, grandfathered status — known before the IMA’s founding, named in 1902.
Found in marine evaporite deposits.
It is found associated with Hematite, carnallite, sylvite, halite, kieserite, anhydrite.
The mineral was named to honor Adolph von Koenen (1837–1915), German geologist of Göttingen, Germany, who discovered the first specimens.
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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