Field of view 5 mm PXRD EDS analysed River-bed Cilaos 55°27'20"E 21°13'27"S May 2008. From: Réunion, France. — Photo: Emil Box · CC0
Reyerite
Reyerite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂Ca₁₄Al₂Si₂₂O₅₈(OH)₈·6H₂O.
It crystallizes in the hexagonal crystal system (space group P-3). It is a member of the Gyrolite structural group.
Key properties: Mohs hardness 3.5–4.5; specific gravity 2.51–2.58; Vitreous luster; optically uniaxial.
IMA symbol Rey, grandfathered status — known before the IMA’s founding, named in 1906.
Found in tuff (Niaqornat, Greenland); in basalt, within the contact aureole of a volcanic plug (Isle of Mull, Scotland); in a low-grade regionally metamorphosed diabase dike (Rawlings quarry, Virginia, USA).
It is found associated with Calcite, chlorite, gyrolite, analcime, pectolite, thomsonite, natrolite.
The name refers to Professor Eduard Reyer (1849–1914), geologist of Vienna, Austria.