Tomichite Mineral Data

General Tomichite Information

Chemical Formula:

(V,Fe)4Ti3AsO13(OH)

Composition:

Molecular Weight = 647.82 gm

Titanium 22.17 % Ti 36.99 % TiO₂

Vanadium 30.67 % V 45.12 % V₂O₃

Iron 0.86 % Fe 1.23 % Fe₂O₃

Arsenic 11.57 % As 17.74 % As₂O₅

Hydrogen 0.16 % H 1.39 % H₂O

Oxygen 34.58 % O

______ ______

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

Tomichite Image

Images:

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

Tomichite Crystallography

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 - PrismaticH-M Symbol (2/m) Space Group: A2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.662(1), 2.836(0.9), 1.572(0.5),

Crystal Structure:

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Grey I E , Madsen I C , Harris D C , American Mineralogist , 72 (1987) p.201-208, Barian tomichite, Ba.5(As2).5Ti2(V,Fe)5O13(OH), its crystal structure and, relationship to derbylite and tomichite

View Additional jPOWD Structure files for Tomichite
[1]

Physical Properties of Tomichite

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

Optical Properties of Tomichite

Optical Data:

Biaxial (?)

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

RL Anisotrophism:

Moderate, yellowish gray to dark gray.

RL Color:

Gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Tomichite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	17.90	18.30
420 nm	17.50	17.90
440 nm	17.20	17.60
460 nm	17.00	17.50
480 nm	17.00	17.50
500 nm	16.90	17.50
520 nm	17.00	17.60
540 nm	17.00	17.70
560 nm	17.10	17.80
580 nm	17.10	17.90
600 nm	17.20	17.90
620 nm	17.20	18.00
640 nm	17.20	18.00
660 nm	17.20	18.00
680 nm	17.30	18.00
700 nm	17.30	18.00

**Calculated Relative Intensity Colors of Tomichite in Air**
Relative Intensity	0%	60%	100%	120%	180%	240%	300%	360%	420%	480%	520%
R₁
R₂

Calculated Properties of Tomichite

Electron Density:

Bulk Density (Electron Density)=4.15 gm/cc
note: Specific Gravity of Tomichite =4.42 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Tomichite= 17.94 barns/electron
U=PE_Tomichite x rElectron Density= 74.50 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tomichite is Not Radioactive

Tomichite Classification

Dana Class:

46.02.03.01 (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites

(46.02)with miscellaneous formulae

(46.02.03)Derbylite Group

46.02.03.01 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m

46.02.03.02 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 2₁/m 2/m

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

04.J - Arsenites, Antimonites, Bismuthites, Sulfites,

04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O

04.JB.55 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 2₁/m 2/m

04.JB.55 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m

04.JB.55 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m

Other Tomichite Information

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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Ask about Tomichite here :
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Print or Cut-and-Paste your Tomichite Specimen Label here :

Tomichite

(V,Fe)4Ti3AsO13(OH)
Dana No: 46.02.03.01 Strunz No: 04.JB.55
Locality:

Notes: