Coronadite

{{Short description|Lead manganese oxide mineral}}

{{Infobox mineral

| name = coronadite

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| image = RM2019-Coronadita.jpg

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| caption = Coronadita

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| category = hydroxides

| formula = Pb(Mn⁴⁺₆Mn³⁺₂)O₁₆

| IMAsymbol = Cor{{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}}

| molweight = 933.55

| strunz = 4/D.08-70

| dana = 7.9.1.4

| system = monoclinic

| class =

| symmetry = I2/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

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| mohs = 4.5–5

| luster = submetallic

| streak = brownish black

| diaphaneity = opaque

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| density = 5.44

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| refractive = 2.72?

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| pleochroism = brown-grey

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| impurities = Fe, Al

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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.{{cite web |title=Coronadite Mineral Data |url=http://webmineral.com/data/Coronadite.shtml |website=webmineral.com}} It is chemically related to ferricoronadite, an {{chem2|Fe3+}} analogue, as well as cryptomelane, hollandite, manjiroite and strontiomelane.

File:Hollandite.jpg|Polyhedral representation of the 2 × 2 tunnel structure of coronadite. The black atoms represent Pb.