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Tomichite Mineral Data
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General Tomichite Information
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 Chemical Formula: |
(V,Fe)4Ti3AsO13(OH) |
| Composition: |
Molecular Weight = 647.82 gm |
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Titanium 22.17 % Ti 36.99 % TiO2 |
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Vanadium 30.67 % V 45.12 % V2O3 |
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Iron 0.86 % Fe 1.23 % Fe2O3 |
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Arsenic 11.57 % As 17.74 % As2O5 |
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Hydrogen 0.16 % H 1.39 % H2O |
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Oxygen 34.58 % O |
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______ ______ |
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100.00 % 102.47 % = TOTAL OXIDE |
| Empirical Formula: |
V3+3.9Fe3+0.1Ti3AsO13(OH) |
| Environment: |
In a specimen from a hydrothermal gold deposit. |
| IMA Status: |
Approved IMA 1979 |
| Locality: |
Kalgoorlie, Western Australia. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Stephan A. Tomich (1914-), consulting geologist who discovered the mineral. |
| Name Pronunciation: |
Tomichite + Pronunciation  |
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Tomichite Image |
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Images:
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Tomichite
Comments: Section of drill core with a very rare crystal of tomichite to 1mm.
Location: Hemlo Gold mine, Ontario, Canada.
Scale: Core size 2.5 cm.
© Tom Loomis / Dakota Matrix |
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Tomichite Crystallography
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| Axial Ratios: |
a:b:c =0.5021:1:0.3521 |
| Cell Dimensions: |
a = 7.119, b = 14.176, c = 4.992, Z = 2; beta = 105.05° V = 486.51 Den(Calc)= 4.42 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: A2/m |
| X Ray Diffraction: |
By Intensity(I/Io): 2.662(1), 2.836(0.9), 1.572(0.5), |
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Physical Properties of Tomichite
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| Cleavage: |
None |
| Color: |
Black. |
| Density: |
4.16 |
| Diaphaneity: |
Opaque |
| Habit: |
Tabular - Form dimensions are thin in one direction. |
| Hardness: |
6 - Orthoclase |
| Luster: |
Resinous |
| Streak: |
black |
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Optical Properties of Tomichite
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| Optical Data: |
Biaxial (?) |
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NCalc= 2.36 - from Gladstone-Dale relationship (KC = 0.3086) where Ncalc=Dcalc*KC+1
NCalc= 2.28 - from Gladstone-Dale relationship (KC = 0.3086) where Ncalc=Dmeas*KC+1
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| RL Anisotrophism: |
Moderate, yellowish gray to dark gray. |
| RL Color: |
Gray. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Tomichite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
17.90 |
18.30 |
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| 420 nm |
17.50 |
17.90 |
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| 440 nm |
17.20 |
17.60 |
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| 460 nm |
17.00 |
17.50 |
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| 480 nm |
17.00 |
17.50 |
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| 500 nm |
16.90 |
17.50 |
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| 520 nm |
17.00 |
17.60 |
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| 540 nm |
17.00 |
17.70 |
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| 560 nm |
17.10 |
17.80 |
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| 580 nm |
17.10 |
17.90 |
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| 600 nm |
17.20 |
17.90 |
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| 620 nm |
17.20 |
18.00 |
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| 640 nm |
17.20 |
18.00 |
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| 660 nm |
17.20 |
18.00 |
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| 680 nm |
17.30 |
18.00 |
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| 700 nm |
17.30 |
18.00 |
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Calculated Relative Intensity Colors of Tomichite in Air
Relative
Intensity |
0% |
60% |
100% |
120% |
180% |
240% |
300% |
360% |
420% |
480% |
520% |
| R1 |
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| R2 |
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Calculated Properties of Tomichite
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| Electron Density: |
Bulk Density (Electron Density)=4.15 gm/cc
note: Specific Gravity of Tomichite =4.42 gm/cc.
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| Fermion Index: |
Fermion Index = 0.02
Boson Index = 0.98 |
| Photoelectric: |
PETomichite = 17.94 barns/electron
U=PETomichite x rElectron Density= 74.50 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tomichite is Not Radioactive |
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Tomichite Classification
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| Dana Class: |
46.02.03.01 (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites |
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(46.02)with miscellaneous formulae |
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(46.02.03)Derbylite Group |
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46.02.03.01 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m |
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46.02.03.02 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 21/m 2/m |
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46.02.03.03 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m |
| Strunz Class: |
04.JB.55 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.J - Arsenites, Antimonites, Bismuthites, Sulfites, |
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04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O |
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04.JB.55 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 21/m 2/m |
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04.JB.55 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m |
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04.JB.55 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m |
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Other Tomichite Information
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| References: |
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic3) |
| See Also: |
Links to other databases for Tomichite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST
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Tomichite
(V,Fe)4Ti3AsO13(OH)
Dana No: 46.02.03.01 Strunz No: 04.JB.55
Locality:
Notes:
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