Weberite (greenish grey) in Kryolite Locality: Ivittuut , Greenland Exposed in the Mineralogical Museum of University Bonn, Germany — Photo: Ra'ike · CC BY-SA 3.0
Weberite
Weberite is an IMA-recognized mineral species in the halide class, with the chemical formula Na₂MgAlF₇.
It crystallizes in the orthorhombic crystal system (space group Imma). It is a member of the Weberite structural group.
Key properties: Mohs hardness 3.5; specific gravity 2.96; White streak; Vitreous luster; optically biaxial.
IMA symbol Web, grandfathered status — known before the IMA’s founding, named in 1938.
Found in the cryolite deposit and overlying pegmatite (Ivigtut, Greenland).
It is found associated with Cryolite, chiolite, jarlite, stenonite, thomsenolite, prosopite, pachnolite, ralstonite, fluorite, topaz, potassian mica, pyrite, galena (Ivigtut, Greenland).
The mineral was named to honor Theobald Weber (1823–1886), active in the early development of the Ivigtut cryolite deposit.