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The Mineral Coronadite

Coronadite, a Lead, Manganese hydrous oxide, is part of the tetravalent Manganese-oxide rich mineral from the family of cryptomelane, which is generally connected with manganese ores of the supergene variety.  Nevertheless, it is also reportedly formed during lateralization. Ehrlich and others located manganese nodules, which were largely made of coronadite formed by epigenetic (formed  after the surrounding rock formation) solution.

Chemical Formula  
Pb (Mn++++, Mn++) 8O16

Derivation of Name  
The coronadite mineral was named after Francisco Vasquez de Coronado (CA 1500-1554), first Spanish explorer of the American southwest.

Occurrence         
The Primary mineral is found in hot springs or hydrothermal veins, while the secondary ones are found in oxidized areas above deposits of Mn and buried sedimentary rocks.  In Wadi Um Ghadah, in Southern Jordan, the manganese   is sandwiched between layers of the arkosic sandstone, while, in that of Wadi Dana, the manganese is mainly found within the Cambrian middle Burj Formation, its numeric member comprising of Dolomite, Limestone and Shale.  Both deposits occur in three zones arranged from bottom to top: the primary sedimentary ore; the supergene stage, and the epigenetic state. 
        
Gemology  
It’s not used as a gemstone.

Source 
You can find this mineral in the Coronado vein, Greenlee County in Arizona. Callenberg North open cut, Callenberg, Glauchau, Saxony and Germany

Mineralogy  
Coronadite is quite an atypical mineral from the oxidation zone, and generally the outcome of concurrent weathering of Pb and Mn-minerals- replacement of Manganese-rich limestones by Lead deposits. Originally this phenomenon was exposed and depicted by an ore vein in the state of Arizona, USA, .
Later it was found associated with Hollandite, Cryptomelane, Kaolinite, Limonite and Quartz in Morocco.   A group of very ordinary, tetragonal and monoclinic-pseudo tetragonal metal manganese oxides may be confused with radiating, acicular to fibrous Pyrolusite, Dorokite And Romanèchite.

Color           
Dark Gray, Black

Density                              
5.53 GM/cc.

Hardness (Mohs):
4½ - 5

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