nagyágite

{{infobox mineral | name = Nagyágite | category = Sulfosalt mineral | image = Nagyagite-163939.jpg | imagesize = 260px | alt = | caption = Nagyágite from Nagyág (Săcărâmb), Romania (image width: 1.5 mm) | formula = {{chem|Pb|5|Au(Te,Sb)}|4|S|(5–8)}} or or | IMAsymbol = Ngy | molweight = | strunz = 2.HB.20a | dana = 02.11.10.01 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = P21/m | color = | colour = Blackish lead-grey; pale grey in polished section | habit = Tabular crystals (often bent), also massive granular, pseudotetragonal | twinning = Crossed twin lamellae observed on (001) sections | cleavage = Perfect on {010}, excellent on {101} | fracture = Hackly | tenacity = Flexible, slightly malleable | mohs = 1.5 | lustre = Metallic, bright on fresh cleavage | streak = Blackish lead-grey | diaphaneity = Opaque | gravity = 7.35–7.49 | density = | polish = | opticalprop = | refractive = | birefringence = | pleochroism = Weak | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} Nagyágite () is a rare sulfide mineral with known occurrence associated with gold ores. Nagyágite crystals are opaque, monoclinic and dark grey to black coloured.

It was first described in 1845 for an occurrence at the type locality of the Nagyág mine, Săcărâmb, Hunedoara County, Romania.