nelenite

{{Infobox mineral | name = Nelenite | image = Nelenite-213099.jpg | alt = | caption = Nelenite (brown) and franklinite (metallic, black), from Franklin, Franklin Mining District, Sussex County, New Jersey, US | category = Phyllosilicate minerals | formula = or | IMAsymbol = Nln | strunz = 9.EE.15 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/m | unit cell = a = 23.24, b = 13.41 c = 7.38 [Å]; β = 105.21°; Z = 2 | color = Light to medium brown | colour = | habit = Coarsely granular to massive | twinning = | cleavage = Perfect on {0001} | fracture = | tenacity = | mohs = 5 | luster = Vitreous, resinous | streak = Light brown | diaphaneity = Transparent | gravity = 3.46 | density = | polish = | opticalprop = Uniaxial (-) | refractive = nω = 1.718 nε = 1.700 | birefringence = δ = 0.018 | pleochroism = Visible ε = colorless and ω = light brown | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | references = }}

Nelenite is a rare manganese iron phyllosilicate arsenate mineral found in Franklin Furnace, New Jersey.