Single perfect colorless crystal of the rare strontium borate mineral strontioginorite from Kohnstein Quarry (Nordhausen, Thuringia, Germany), one of the only three known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Strontioginorite
Strontioginorite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula CaSrB₁₄O₂₀(OH)₆·5H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/a).
Key properties: Mohs hardness 2–3; specific gravity 2.25; Silky luster; optically biaxial.
IMA symbol Sgnr, grandfathered status — known before the IMA’s founding, named in 1959.
A rare insoluble residue in salt beds (Königshall-Hindenburg mine, Germany).
It is found associated with Halite, anhydrite (Königshall-Hindenburg mine, Germany); halite, sylvite, hilgardite, volkovskite, trembathite, danburite, howlite, veatchite.
As the strontium analog of ginorite.