A nodule of white fine fibrous lüneburgite. A fine example of this uncommon borate from the type locality (Lüneburg, Lower Saxony, Germany). Ex. Erich Laskowski collection. — Photo: David Hospital · CC BY-SA 4.0
Lüneburgite
Lüneburgite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Mg₃[B₂(OH)₆(PO₄)₂]·6H₂O.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: Mohs hardness 2; specific gravity 2.05; Vitreous luster; optically biaxial.
IMA symbol Lbu, grandfathered status — known before the IMA’s founding, named in 1870.
Found in marine evaporite sequences.
It is found associated with Boracite, gypsum (Liineburg, Germany); colemanite, howlite, searlesite, magnesite, dolomite (Bela Stena, Serbia); halite, sylvite, polyhalite (Permian Basin.
The name refers to its first-noted occurrence at Liineburg, Germany.