crystals of haüyne, crystals of calcite, crystals of pyrite : Sar-e-Sang River,Sar-e-Sang (Sar Sang ; Sary Sang), Koksha Valley (Kokscha Valley ; Kokcha Valley) — Photo: Parent Géry · CC BY-SA 3.0
Haüyne
A rare blue tectosilicate of the sodalite group carrying sulfate — the deep-blue mineral that colors volcanic rocks like those of the Eifel.
Intro adapted from Wikipedia (CC BY-SA).
Haüyne is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₃Ca(Si₃Al₃)O₁₂(SO₄).
It crystallizes in the cubic crystal system (space group P-43n). It is a member of the Cancrinite-sodalite, Sodalite structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 2.44–2.5; typically blue or white or green or yellow; Slightly bluish to colorless streak; Vitreous to greasy luster; refractive index 1.502; optically isotropic.
IMA symbol Hyn, grandfathered status — known before the IMA’s founding, named in 1807.
Found in phonolites and related leucite- or nepheline-rich igneous rocks; less commonly in nepheline-free extrusives.
It is found associated with Nepheline, leucite, titanian andradite, melilite, augite, sanidine, biotite, phlogopite, apatite.
The mineral was named to honor Abb¶e Ren¶e Just HaÄ uy (1743–1822), French crystallographer and mineralogist.
Collections: Collector Favorites, Rare & Remarkable.