Outstanding green crystals of the extremely rare Ba-Fe silicate mineral andremeyerite from the type locality in DR Congo (Nyiragongo Volcano, Nyiragongo Territory, North Kivu, DR Congo), and only one of the two known localities worldwide, being the other a slag locality. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Andrémeyerite
Andrémeyerite is an IMA-recognized mineral species in the silicate class, with the chemical formula BaFe²⁺₂(Si₂O₇).
It crystallizes in the monoclinic crystal system (space group Bmcb).
Key properties: Mohs hardness 5.5; specific gravity 4.15; optically biaxial.
IMA symbol Amy, IMA status: approved, named in 1972.
Found in vesicles of melilite-leucite-nephelinite; may represent crystallization of an associated green glass.
It is found associated with Nepheline, leucite, clinopyroxene, kirschsteinite, melilite, apatite, magnetite, gÄotzenite, troilite, glass.
The mineral was named to honor Andr¶e Marie Meyer (1890{?), Belgian geologist with the Geological Survey of the Belgian Congo, who first collected the mineral.