coronadite | |
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![]() Coronadita | |
General | |
Category | hydroxides |
Formula (repeating unit) | Pb(Mn4+6Mn3+2)O16 |
IMA symbol | Cor[1] |
Strunz classification | 4/D.08-70 |
Dana classification | 7.9.1.4 |
Crystal system | monoclinic |
Space group | I2/m |
Unit cell | a = 9.938, b = 2.8678, c = 9.834, Z = 1; β = 90.39° V = 280.26 |
Identification | |
Formula mass | 933.55 |
Colour | dark grey to black |
Crystal habit | botryoidal; fibrous |
Mohs scale hardness | 4.5–5 |
Luster | submetallic |
Streak | brownish black |
Diaphaneity | opaque |
Density | 5.44 |
Refractive index | 2.72? |
Pleochroism | brown-grey |
Common impurities | Fe, Al |
Coronadite is the lead endmember of the hollandite 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.[2]
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Polyhedral representation of the 2 × 2 tunnel structure of coronadite. The black atoms represent Pb.
References
[edit]- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ "Coronadite Mineral Data". webmineral.com.