Tomichite Mineral Data   Search Webmineral :     Home Crystal jmol jPOWD Chem X Ray Dana Strunz Properties A to Z

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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
X Ray Diffraction:	By Intensity(I/Io): 2.662(1), 2.836(0.9), 1.572(0.5),
Crystal Structure: Mouse drag1 - LMB Manipulate Structure drag2 - RMB Resize/Rotate Keyboard S - Stereo Pair on/off H - Help Screen I - Data Info A - Atoms On/Off P - Polyhedra On/Off B - Bonds On/Off Help on Above	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 Properties of Tomichite

Tomichite Classification

Other Tomichite Information

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