Todorokite with manjioite and calcite from the Smartt Mine, Kuruman District, South Africa
General
Category
Manganese minerals
Formula (repeating unit)
(Na,Ca,K,Ba,Sr) 1-x(Mn,Mg,Al) 6O 12·3-4H 2O[1]
IMA symbol
Tdr[2]
Strunz classification
4.DK.10 (10 ed) 4/D.09-10 (8 ed)
Dana classification
7.8.1.1
Crystal system
Monoclinic
Crystal class
Prismatic (2/m) (same H-M symbol)
Space group
P2/m (no. 11)
Identification
Formula mass
583.05 g/mol
Color
Dark brown or brownish black, brown in transmitted light
Crystal habit
Aggregates of minute lathlike crystals
Twinning
Contact twins are common
Cleavage
Perfect on {100} and {010}
Mohs scale hardness
1+1⁄2
Luster
Metallic to dull, silky in aggregates
Streak
Black or dark brown
Diaphaneity
Opaque, transparent in very thin slivers
Specific gravity
3.5 to 3.8
Optical properties
Biaxial
Refractive index
Greater than 1.74
Birefringence
nearly 0.02[3]
Pleochroism
X = dark brown, Z = yellowish brown[4]
Fusibility
Does not fuse[3]
Solubility
Soluble in acids[3]
References
[5][6][7][8]
Polyhedral representation of the todorokite structure.[9]
Todorokite is a complex hydrous manganese oxide mineral with generic chemical formula (Na,Ca,K,Ba,Sr) 1-x(Mn,Mg,Al) 6O 12·3-4H 2O.[1] It was named in 1934 for the type locality, the Todoroki mine, Hokkaido, Japan. It belongs to the prismatic class 2/m of the monoclinic crystal system, but the angle β between the a and c axes is close to 90°, making it seem orthorhombic. It is a brown to black mineral which occurs in massive or tuberose forms. It is quite soft with a Mohs hardness of 1.5, and a specific gravity of 3.49 – 3.82. It is a component of deep ocean basin manganese nodules.
^ ab"IMA Mineral List with Database of Mineral Properties".
^ abcFoshag W F (1935) New mineral names, American Mineralogist 20, 678–678. Summary of article by Yoshimura in the Journal of the Faculty of Science, Hokkaido Imperial University, Ser. IV, Geol and Min 2, no 4:289–297 (1934)
^Frondel, Marvin and Ito (1960) American Mineralogist 45: 1167–1173
^Gaines et al (1997) Dana’s New Mineralogy Eighth Edition. Wiley
^Webmineral data
^Mindat.org
^Handbook of Mineralogy
^Post, Heaney and Hanson (2003) American Mineralogist 88: 142–150
Todorokite is a complex hydrous manganese oxide mineral with generic chemical formula (Na,Ca,K,Ba,Sr) 1-x(Mn,Mg,Al) 6O 12·3-4H 2O. It was named in 1934...
columbite and tantalite series Galaxite, MnIIAl2O4, a spinel mineral Todorokite, (Na,Ca,K,Ba,Sr) 1-x(Mn,Mg,Al) 6O 12·3-4H 2O, a rare complex hydrous manganese...
asbolane-buserite while diagenetic nodules are dominated by buserite I, birnessite, todorokite, and asbolane-buserite. The growth types termed diagenetic and hydrogenetic...
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cone-shaped formations of ferromanganese composition contain the mineral todorokite, which is common only in hot spring sediments. Thus, events with the formation...
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manganese oxides. He also discussed the tunnel structure of hollandites and todorokites along with the interlayer spacings of managanese oxides. In the early...
(IMA1970-024): Burns, R G; Burns, V E; Stockman, H W (1983). "A review of the todorokite-buserite problem: implications to the mineralogy of marine manganese nodules"...
clay, feldspar, ferrihydrite, feroxyhyte, goethite, hematite, quartz and todorokite and reach thicknesses of 10 centimetres (3.9 in), although they only cover...
Components include asbolane, carbonate fluorapatite, goethite, palygorskite, todorokite and vernadite as well as minor calcite and quartz; the crusts which occur...
proportion of unstable heavy minerals (pyrolusite, manganite, birnessite, todorokite and rhodochrosite) in the Toarcian clays, that indicate basaltic volcanism...
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