Green crystals of the rare copper-lead silicate luddenite from Rawhide Mine (Rawhide Wash, Arizona, United States of America), one of the only three known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Luddenite
Luddenite is an IMA-recognized mineral species in the silicate class, with the chemical formula Cu₂Pb₂Si₅O₁₄·14H₂O.
It crystallizes in the monoclinic crystal system.
Key properties: Mohs hardness 4; specific gravity 4.45; Slightly paler nickel green streak; optically biaxial.
IMA symbol Ldd, IMA status: approved, named in 1981.
Found in thoroughly oxidized Pb{Cu sulfide ores.
It is found associated with Galena, chalcopyrite, fluorite, quartz, alamosite, melanotekite, cerussite, chalcocite, shattuckite, chrysocolla, wickenburgite, altered Fe-Ti oxides.
The name refers to Raymond W. Ludden, Chief Geologist for Western Exploration, Phelps Dodge Corporation.