Coronadite

{{Short description|Lead manganese oxide mineral}} {{Infobox mineral | name = coronadite | boxwidth = | boxbgcolor = | image = RM2019-Coronadita.jpg | imagesize = | alt = | caption = Coronadita | struct image = | struct caption = | struct imagesize = | struct2 image = | struct2 caption = | struct2 imagesize= | SMILES = | Jmol = | category = hydroxides | formula = Pb(Mn⁴⁺₆Mn³⁺₂)O₁₆ | IMAsymbol = Cor<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|journal=Mineralogical Magazine|volume=85|issue=3 |pages=291–320|doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free|url-access=subscription}}</ref> | molweight = 933.55 | strunz = 4/D.08-70 | dana = 7.9.1.4 | system = monoclinic | class = | symmetry = ''I''2/''m'' | unit cell = a = 9.938, b = 2.8678, c = 9.834, Z = 1; β = 90.39° V = 280.26 | color = | colour = dark grey to black | habit = botryoidal; fibrous | twinning = | cleavage = | fracture = | tenacity = | toughness = | mohs = 4.5–5 | luster = submetallic | streak = brownish black | diaphaneity = opaque | gravity = | density = 5.44 | polish = | opticalprop = | refractive = 2.72? | birefringence = | pleochroism = brown-grey | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | Curie temp = | fusibility = | diagnostic = | solubility = | impurities = Fe, Al | alteration = | other = | prop1 = | prop1text = | references = | var1 = | var1text = | var2 = | var2text = | var3 = | var3text = | var4 = | var4text = | var5 = | var5text = | var6 = | var6text = }} '''Coronadite''' is the lead endmember of the coronadite group, a family of tectomanganates with a 2 × 2 tunnel structure. The mineral was named after Francisco Vasquez de Coronado who was an explorer of southwest US. The name was made up by Waldemar Lindgren in 1905.<ref>{{cite web |title=Coronadite Mineral Data |url=http://webmineral.com/data/Coronadite.shtml |website=webmineral.com}}</ref> It is chemically related to ferricoronadite, an {{chem2|Fe3+}} analogue, as well as cryptomelane, hollandite, manjiroite and strontiomelane.

<gallery widths="200px" heights="200px" perrow="1"> File:Hollandite.jpg|Polyhedral representation of the 2 × 2 tunnel structure of coronadite. The black atoms represent Pb. </gallery>

==References== {{Reflist}}

Category:Manganese minerals Category:Lead minerals Category:Minerals described in 1904