NAGYÁGITE
Class : Sulfides and sulfosalts
Subclass : Sulfides
Crystal system : Tetragonal
Chemistry : (Pb,Sb)2(Au,Te)S2
Rarity : Rare
Nagyágite is a rare primary metallic mineral from epithermal gold deposits. It is one of the rare gold sulfides, which accompanies telluride deposits (hessite, calaverite, sylvanite), native gold and base metal sulfides in its deposits. Its name comes from its locality of discovery : Nagyág (currently Sacarimb) in Romania. With a metallic luster and a bluish lead gray color, it occurs in granular masses, sometimes in fine striated rectangular tabular crystals, or in leafy, twisted strips with jagged edges. It is a very minor gold ore and a minor tellurium ore.
Main photo : 5 cm nagyágite blades in rhodochrosite from Sacaramb, Romania © Rob Lavinsky
Nagyágite in the World
Twinning
Multiple twins on (001) are common.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 1 to 1.5
Density : 7.35 to 7.49
Fracture : Undetermined
Streak : Gray-black
TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None
Solubility : Nitric acid
Magnetism : NoneRadioactivity : None