Todorokite Locality: Kent, Kazakhstan Size: miniature, 4.7 x 3.9 x 2.4 cm Todorokite An unusual, organic-looking , stalactiticgrowth of this complex manganese oxide which has the kitchen sink thrown into its chemistry. It is likely that this is the same locality reported on mindat as Ushkatan, mis-transliterated. In any case,a very good example of this complex oxide. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Todorokite
A tunnel-structured hydrous manganese oxide — a major component of deep-sea manganese nodules.
Intro adapted from Wikipedia (CC BY-SA).
Todorokite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Na,Ca,K,Ba,Sr)₁₋ₓ(Mn,Mg,Al)₆O₁₂·3-4H₂O.
It crystallizes in the monoclinic crystal system (space group P2/m).
Key properties: Mohs hardness 1.33; specific gravity 3.66; Black streak; Metallic to dull; silky in aggregates luster; refractive index 1.74; optically biaxial.
IMA symbol Tdr, IMA status: approved, named in 1934.
A secondary mineral produced from weathering or hydrothermal alteration of other manganese-bearing species; in sedimentary marine fumarolic deposits; the principal manganese oxide in deep-sea manganese nodules.
It is found associated with Pyrolusite, cryptomelane, romanèchite, manganite, rhodochrosite, quartz, “opal”.
The name refers to its first-noted occurrence in the Todoroki mine, Japan.