Ottrelite Mineral Data

General Ottrelite Information

Chemical Formula:

(Mn,Fe++,Mg)2Al4Si2O10(OH)4

Composition:

Molecular Weight = 490.11 gm

Magnesium 2.48 % Mg 4.11 % MgO

Manganese 10.09 % Mn 13.03 % MnO

Aluminum 21.47 % Al 40.57 % Al₂O₃

Iron 7.98 % Fe 8.80 % FeO / 1.63 % Fe₂O₃

Silicon 11.46 % Si 24.52 % SiO₂

Hydrogen 0.82 % H 7.35 % H₂O

Oxygen 45.70 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺_0.9Fe²⁺_0.6Mg_0.5Al_3.9Fe³⁺_0.1Si₂O₁₀(OH)₄

Environment:

Formed under non-shearing stress conditions in veins and cavities within low- to medium-grade metamorphic rocks.

IMA Status:

Valid Species (Pre-IMA) 1819

Locality:

In Belgium, in the Ardennes Mountains, from Ottre, Salmchateau, and Veilsalm. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Ottrelite + Pronunciation

Ottrelite Image

Images:

Ottrelite

Comments: Dark green crystalline ottrelite in quartz.
Location: Vielsalm, Luxembourg, Belgium. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ottrelite Crystallography

Axial Ratios:

a:b:c =1.7332:1:3.3212

Cell Dimensions:

a = 9.505, b = 5.484, c = 18.214, Z = 4; beta = 101.767° V = 929.46 Den(Calc)= 3.50

Crystal System:

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

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

By Intensity(I/I_o): 4.46(1), 2.973(0.8), 2.686(0.45),1.585(0.4), 2.439(0.4), 2.461(0.25), 2.375(0.2),

Physical Properties of Ottrelite

Cleavage:

{001} Perfect, {110} Indistinct

Color:

Pistachio green.

Density:

3.52

Diaphaneity:

Translucent

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Scaly - Morphology like fish scales.

Hardness:

6-7 - Orthoclase-Quartz

Luster:

Vitreous (Glassy)

Streak:

greenish gray

Optical Properties of Ottrelite

Gladstone-Dale:

CI meas= 0.051 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.046 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2057,KPDmeas= 0.2045,KC= 0.2155
Ncalc = 1.75 - 1.76

Optical Data:

Biaxial (+), a=1.709-1.725, b=1.712-1.726, g=1.716-1.732, bire=0.0070, 2V(Calc)=46-82, 2V(Meas)=46-70. Dispersion r > v strong.

Pleochroism (x):

olive yellow.

Pleochroism (y):

pale greenish yellow.

Pleochroism (z):

very light yellow.

Calculated Properties of Ottrelite

Electron Density:

Bulk Density (Electron Density)=3.45 gm/cc
note: Specific Gravity of Ottrelite =3.50 gm/cc.

Fermion Index:

Fermion Index = 0.0097433358
Boson Index = 0.9902566642

Photoelectric:

PE_Ottrelite= 6.03 barns/electron
U=PE_Ottrelite x rElectron Density= 20.79 barns/cc.

Radioactivity:

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

Ottrelite Classification

Dana Class:

52.03.03.03 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.03)with cations in [6] coordination only

(52.03.03)Chloritoid group

52.03.03.01 Chloritoid (Fe,Mg,Mn)2Al4Si2O10(OH)4 P1 1

52.03.03.02 Magnesiochloritoid MgAl2SiO5(OH)2 C 2/c 2/m

52.03.03.03 Ottrelite (Mn,Fe,Mg)2Al4Si2O10(OH)4 C 2/c 2/m

52.03.03.04 Carboirite-VIII Fe(Al,Ge)2O[(Ge,Si)O4](OH)2 C1 1

Strunz Class:

09.AF.85 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AF -Nesosilicates with additional anions;

09.AF.85 Chloritoid (Fe,Mg,Mn)2Al4Si2O10(OH)4 P1 1

09.AF.85 Magnesiochloritoid MgAl2SiO5(OH)2 C 2/c 2/m

09.AF.85 Ottrelite (Mn,Fe,Mg)2Al4Si2O10(OH)4 C 2/c 2/m

Other Ottrelite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(AntBidBlaNic2)

See Also:

Links to other databases for Ottrelite :
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

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

Ottrelite

(Mn,Fe++,Mg)2Al4Si2O10(OH)4
Dana No: 52.03.03.03 Strunz No: 09.AF.85
Locality:

Notes: