Carmichaelite Mineral Data

General Carmichaelite Information

Chemical Formula:

(Ti,Cr,Fe)[O2-x(OH)x],x~0.5

Composition:

Molecular Weight = 76.54 gm

Titanium 38.79 % Ti 64.71 % TiO₂

Chromium 12.91 % Cr 16.88 % CrO

Iron 5.84 % Fe 7.51 % FeO

Hydrogen 0.66 % H 5.88 % H₂O

Oxygen 41.81 % O

______ ______

100.00 % 94.98 % = TOTAL OXIDE

Empirical Formula:

Ti_0.62Cr_0.19Fe²⁺_0.08O_1.5(OH)_0.5

Environment:

Microscopic inclusions in mantle-derived pyrope crystals. The mineral is inferred to have co-precipitated with the pyrope host in the presence of a fluid or melt phase at 650-750 de g C and 20-25 kbar pressures.

IMA Status:

Approved IMA 1996 (Dana # Added)

Locality:

Garnet Ridge, an ultramafic diatreme on the Colorado Plateau in Arizona, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Ian S. E. Charmchael, Professor of Geology at the University of California, Berkeley, in recognition

Synonym:

ICSD 89831

IMA1996-062

Carmichaelite Image

Images:

Carmichaelite

Comments: Backscattered electron (BSE) image of a grain of carmichaelite included in pyrope in GRPy-40. (AmMin 85:794).
Location: Garnet Ridge, an ultramafic diatreme on the Colorado Plateau in Arizona.. Scale: See Image.
© American Mineralogist

Carmichaelite Crystallography

Axial Ratios:

a:b:c =1.6905:1:4.4286

Cell Dimensions:

a = 7.706, b = 4.5583, c = 20.187, Z = 22; beta = 92.334° V = 708.51 Den(Calc)= 3.95

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 2.842(1)(115), 3.773(0.94)(013), 2.664(0.7)(213),1.688(0.54)(322), 1.661(0.44)(128), 1.679(0.44)(226), 1.648(0.34)(1.1.11),

Crystal Structure:

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Wang L , Rouse R C , Essene E J , Peacor D R , Zhang Y , American Mineralogist , 85 (2000) p.792-800, Carmichaelite, a new hydroxyl-bearing titanate from Garnet Ridge, Arizona

Physical Properties of Carmichaelite

Cleavage:

None

Color:

Cinnamon brown, Black.

Diaphaneity:

Opaque to translucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Inclusions - Generally found as inclusions in other minerals.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

6 - Orthoclase

Luster:

Metallic

Optical Properties of Carmichaelite

Gladstone-Dale:

CI calc= -0.138 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.3671,KC= 0.3225
Ncalc = 2.27

Optical Data:

Biaxial (?), b=2-2.9

Calculated Properties of Carmichaelite

Electron Density:

Bulk Density (Electron Density)=3.80 gm/cc
note: Specific Gravity of Carmichaelite =3.95 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_{Carmichaelite}= 11.14 barns/electron
U=PE_{Carmichaelite} x rElectron Density= 42.30 barns/cc.

Radioactivity:

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

Carmichaelite Classification

Dana Class:

08.07.13.01 (08)Multiple Oxides with Nb, Ta, and Ti

(08.07)Dana Type

(08.07.13)Dana Group

08.07.13.01 Carmichaelite! (Ti,Cr,Fe)[O2-x(OH)x],x~0.5 P 2₁/c 2/m

Strunz Class:

04.DB.50 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DB -With medium-sized cations; chains of edge-sharing octahedra

04.DB.50 Carmichaelite! (Ti,Cr,Fe)[O2-x(OH)x],x~0.5 P 2₁/c 2/m

Other Carmichaelite Information

References:

NAME( AmMin, Vol 85, p 792) PHYS. PROP.(AmMin, Vol 85, p 792) OPTIC PROP.(AmMin, Vol 85, p 792)

See Also:

Links to other databases for Carmichaelite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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Print or Cut-and-Paste your Carmichaelite Specimen Label here :

Carmichaelite

(Ti,Cr,Fe)[O2-x(OH)x],x~0.5
Dana No: 08.07.13.01 Strunz No: 04.DB.50
Locality:

Notes: