tyuyamunite

{{Infobox mineral | name = Tyuyamunite | image = Tyuyamunite-286294.jpg | imagesize = 260px | alt = | caption = | category = Vanadate mineral | formula = Ca(UO2)2V2O8·(5–8)H2O | IMAsymbol = Tyu | molweight = | strunz = 4.HB.25 | dana = 40.2a.26.1 | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Pnna | unit cell = a = 10.63 Å, b = 28.36 Å c = 20.4 Å; Z = 4 | color = | colour = Canary yellow, lemon-yellow; greenish yellow (upon exposure to sunlight) | habit = Platy crystals often in radiating sprays, coatings, massive | twinning = | cleavage = Perfect on {001}, micaceous; distinct on {100} & {010} | fracture = | tenacity = | mohs = – 2 | lustre = Adamantine, waxy, pearly on {101}, dull | streak = Yellow | diaphaneity = Translucent to opaque | gravity = 3.57 – 4.35 | density = | polish = | opticalprop = Biaxial (−) | refractive = nα = 1.675 nβ = 1.860 – 1.870 nγ = 1.885 – 1.895 | birefringence = 0.210 – 0.220 | pleochroism = weak: X = nearly colourless, Y = pale canary yellow, Z = canary yellow | 2V = 30° to 45° | dispersion = none | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = 25px Radioactive | prop1 = | prop1text = | references = }} Tyuyamunite (pronounced tuh-YOO-ya-moon-ite) is a very rare uranium mineral with formula Ca(UO2)2V2O8·(5–8)H2O. It is a member of the carnotite group. It is a bright, canary-yellow color because of its high uranium content. Also, because of tyuyamunite's high uranium content, it is radioactive. It was named by Konstantin Avtonomovich Nenadkevich, in 1912, after its type locality, Tyuya-Muyun, Fergana Valley, Kyrgyzstan.

==Formation and transformation== Tyuyamunite is formed by the weathering of uraninite, a uranium-bearing mineral. Tyuyamunite, being a hydrous mineral, contains water. Yet when it is exposed to the atmosphere it loses its water. This process changes tyuyamunite into a different mineral known as metatyuyamunite Ca(UO2)2(VO4)2·3-5H2O.