Alamosite, Melanotekite Locality: Tsumeb Mine (Tsumcorp Mine), Tsumeb, Otjikoto (Oshikoto) Region, Namibia (Locality at mindat.org) Size: thumbnail, 1.9 x 1.9 x — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Melanotekite
Melanotekite is an IMA-recognized mineral species in the silicate class, with the chemical formula Pb₂Fe³⁺₂O₂(Si₂O₇).
It crystallizes in the orthorhombic crystal system (space group Pbcn).
Key properties: Mohs hardness 6.5; specific gravity 5.73–6.28; typically black or gray; Greenish gray streak; Metallic to greasy luster; optically biaxial.
IMA symbol Mtk, grandfathered status — known before the IMA’s founding, named in 1880.
Found in a metamorphosed Fe{Mn deposit, from which over one ton was removed (Lº angban, Sweden); in oxidized Pb{Cu ores (Artillery Peaks, Arizona, USA).
It is found associated with Lead, magnetite, garnet (Lº angban, Sweden); leadhillite, alamosite (Tsumeb, Namibia); diaboleite (Tiger, Arizona, USA); luddenite, alamosite, shattuckite.
Its name comes from the Greek black and to melt or glass, for the black bead formed under the blowpipe.
Collections: Collector Favorites, Rare & Remarkable.