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Todorokite Mineral Data
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General Todorokite Information
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 Chemical Formula: |
(Na,Ca,K)2(Mn++++,Mn+++)6O12•3-4.5(H2O) |
| Composition: |
Molecular Weight = 583.05 gm |
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Potassium 0.13 % K 0.16 % K2O |
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Sodium 0.79 % Na 1.06 % Na2O |
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Calcium 0.34 % Ca 0.48 % CaO |
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Manganese 56.54 % Mn 27.08 % Mn2O3 / 59.64 % MnO2 |
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Hydrogen 1.04 % H 9.27 % H2O |
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Oxygen 41.16 % O |
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______ ______ |
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100.00 % 97.69 % = TOTAL OXIDE |
| Empirical Formula: |
Na0.2Ca0.05K0.02Mn4+4Mn3+2O12•3(H2O) |
| Environment: |
Primarily found as a constituent mineral in deep sea nodules. |
| IMA Status: |
Valid Species (Pre-IMA) 1934 |
| Locality: |
Todroki mine, Hikkaido, Japan. Link to MinDat.org Location Data. |
| Name Origin: |
Named for the locality. |
| Name Pronunciation: |
Todorokite + Pronunciation  |
| Synonym: |
ICSD 202725 |
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PDF 38-475 |
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Todorokite Image |
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Images:
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Todorokite Crystallography
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| Axial Ratios: |
a:b:c =3.4356:1:3.3606 |
| Cell Dimensions: |
a = 9.764, b = 2.842, c = 9.551, Z = 1; beta = 94.14° V = 264.34 Den(Calc)= 3.66 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/m |
| X Ray Diffraction: |
By Intensity(I/Io): 9.68(1), 4.8(0.8), 2.39(0.4), |
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Physical Properties of Todorokite
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| Cleavage: |
{100} Perfect, {010} Perfect |
| Color: |
Brownish black, Gray, Grayish black, Dark brown, Black. |
| Density: |
3.49 - 3.82, Average = 3.65 |
| Diaphaneity: |
Opaque |
| Habit: |
Aggregates - Made of numerous individual crystals or clusters. |
| Habit: |
Nodular - Tuberose forms having irregular protuberances over the surface. |
| Habit: |
Reniform - "Kidney like" in shape (e.g.. hematite). |
| Hardness: |
1.5 - Between Talc and Gypsum |
| Luster: |
Metallic - Dull |
| Streak: |
dark brown |
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Optical Properties of Todorokite
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| Optical Data: |
Biaxial (?) |
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NCalc= 2.29 - from Gladstone-Dale relationship (KC = 0.3514) where Ncalc=Dcalc*KC+1
NCalc= 2.28 - from Gladstone-Dale relationship (KC = 0.3514) where Ncalc=Dmeas*KC+1
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| Pleochroism (x): |
dark brown. |
| Pleochroism (y): |
brownish. |
| Pleochroism (z): |
yellowish brown. |
| RL Anisotrophism: |
Very strong, bluish or brownish. |
| RL Color: |
Gray white. |
| RL Pleochroism: |
Strong to faint. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Todorokite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
13.90 |
24.70 |
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| 420 nm |
13.20 |
24.20 |
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| 440 nm |
12.50 |
23.70 |
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| 460 nm |
11.70 |
22.00 |
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| 480 nm |
11.10 |
20.60 |
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| 500 nm |
10.60 |
19.40 |
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| 520 nm |
10.20 |
18.60 |
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| 540 nm |
10.00 |
17.90 |
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| 560 nm |
9.70 |
17.30 |
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| 580 nm |
9.50 |
16.80 |
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| 600 nm |
9.30 |
16.40 |
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| 620 nm |
9.10 |
16.10 |
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| 640 nm |
9.00 |
15.80 |
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| 660 nm |
9.00 |
15.50 |
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| 680 nm |
8.90 |
15.30 |
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| 700 nm |
8.90 |
15.10 |
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Calculated Relative Intensity Colors of Todorokite in Air
Relative
Intensity |
0% |
100% |
200% |
300% |
400% |
500% |
600% |
700% |
800% |
900% |
910% |
| R1 |
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| R2 |
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Calculated Properties of Todorokite
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| Electron Density: |
Bulk Density (Electron Density)=3.51 gm/cc
note: Specific Gravity of Todorokite =3.66 gm/cc.
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| Fermion Index: |
Fermion Index = 0.0002039307
Boson Index = 0.9997960693 |
| Photoelectric: |
PETodorokite = 14.72 barns/electron
U=PETodorokite x relectron= 51.66 barns/cc.
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| Radioactivity: |
GRapi = 1.87 (Gamma Ray American Petroleum Institute Units)
Concentration of Todorokite per GRapi unit = 53.41 (%)
Estimated Radioactivity from Todorokite  - barely detectable
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Todorokite Classification
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| Dana Class: |
07.08.01.01 (07)Multiple Oxides |
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(07.08)where A B (O)2�x(H2O) |
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(07.08.01)Dana Group |
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07.08.01.01 Todorokite (Na,Ca,K)2(Mn,Mn)6O12•3-4.5(H2O) P 2/m 2/m |
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07.08.01.02 Woodruffite (Zn,Mn)2Mn5O12•4(H2O) Unk Tetra |
| Strunz Class: |
04.DK.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.D - Metal:Oxygen = 1:2 and similar |
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04.DK -With large (� medium-sized) cations; tunnel structures |
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04.DK.10 Cryptomelane K(Mn,Mn)8O16 I2/m 2/m |
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04.DK.10 Todorokite (Na,Ca,K)2(Mn,Mn)6O12•3-4.5(H2O) P 2/m 2/m |
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04.DK.10 Romanechite (Ba,H2O)2(Mn,Mn)5O10 C 2/m 2/m |
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04.DK.10 Strontiomelane! SrMn6Mn2O16 P 21/m 2/m |
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Other Todorokite Information
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| References: |
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic3) |
| See Also: |
Links to other databases for Todorokite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST
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Todorokite
(Na,Ca,K)2(Mn++++,Mn+++)6O12•3-4.5(H2O)
Dana No: 07.08.01.01 Strunz No: 04.DK.10
Locality:
Notes:
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