Outstanding acicular metallic crystals of the very rare mercury mineral gortdrumite associated to red cinnabar from the famous Moschellandsberg mine (Landsberg, Rhineland-Palatinate, Germany) and only one of four known localities worldwide. Analyzed specimen by REM/EDS. — Photo: David Hospital · CC BY-SA 4.0
Gortdrumite
Gortdrumite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Cu₂₄Fe₂Hg₉S₂₃.
It crystallizes in the orthorhombic crystal system.
Key properties: specific gravity 6.8; Metallic. Anisotropism: Strong, with colors from grayish white with a bluish tint to blue. R1 –R2: (400) 28.0–31.4 luster.
IMA symbol Gdr, IMA status: approved, named in 1979.
Admixed with other sulfide minerals in a vein cutting dolomitized limestone; mineral associations suggest formation at less than 200 ° C.
It is found associated with Chalcopyrite, bornite, chalcocite, cinnabar, ferroan dolomite, barite.
The name is taken from the type locality, the Gortdrum deposit, Ireland.