segnitite

{{Infobox mineral | name = Segnitite | category = Arsenate minerals | image = Segnitite-Lepidocrocite-170219.jpg | imagesize = | caption = Segnitite with lepidocrocite from the Alto das Quelhas do Gestoso Mines, Gestoso, Manhouce, São Pedro do Sul, Viseu District, Portugal. Picture width 1 mm. Yellow brown segnitite with red brown lepidocrocite. | formula = Lead iron(III) arsenate, | IMAsymbol = Sgt | strunz = 7/B.36-165 | dana = 42.7.4.4 | symmetry = Rm | unit cell = a = 7.359(3) Å, c = 17.113(8) Å, V = 802.6(6) Å3+, Z = 6 | color = Greenish brown to yellowish brown and dark brown | habit = Tabular, rhombohedral, pseudo-octahedral, pseudo-cubic and very rarely also acicular crystals. | system = Trigonal | class = Hexagonal scalenohedral – m (2/m) | twinning = Not well observed | cleavage = Distinct on {001} | fracture = Rough, irregular, uneven | tenacity = Brittle | mohs = 4 | luster = Adamantine to vitreous | streak = Pale yellow | diaphaneity = Transparent to translucent | gravity = 4.2 | density = | opticalprop = Uniaxial (−), e=1.955, w=1.975 | refractive = nω = 1.955 to 1.975, nε = 1.975 | birefringence = δ = 0.020 | pleochroism = Pale to moderate yellow | references = }}

Segnitite is a lead iron(III) arsenate mineral. Segnitite was first found in the Broken Hill ore deposit in Broken Hill, New South Wales, Australia. In 1991, segnitite was approved as a new mineral. Segnitite has since been found worldwide near similar locality types where rocks are rich in zinc and lead especially. it was named for Australian mineralogist, gemologist and petrologist Edgar Ralph Segnit. The mineral was named after E. R. Segnit due to his contributions to Australian mineralogy.