Pyrochroite Mineral Data

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General Pyrochroite Information

Chemical Formula:

Mn(OH)2

Composition:

Molecular Weight = 88.95 gm

Manganese 61.76 % Mn 79.75 % MnO

Hydrogen 2.27 % H 20.25 % H₂O

Oxygen 35.97 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺(OH)₂

Environment:

Secondary mineral after hausmannite.

IMA Status:

Valid Species (Pre-IMA) 1864

Locality:

Vermland at Pajsberg near Persberg, Sweden. Link to MinDat.org Location Data.

Name Origin:

Named from the Greek, puro, "fire" and khroma, "color", because of the change in color upon ignition.

Name Pronunciation:

Pyrochroite + Pronunciation

Synonym:

ICSD 23591

PDF 18-787

Pyrochroite Image

Images:

Pyrochroite

Comments: Pseudo-cubic crystal of pyrochroite on matrix.
Location: Franklin, Sussex County, New Jersey, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Pyrochroite Shigaite

Comments: Bronzy yellow crystals of shigaite set in a crystalline matrix of reddish black pychroite.
Location: N'Chwaning Mine, Kalahari Manganese Field, Northern Cape Province, South Africa. Scale: 2.8 x 2.3 cm.
© John Veevaert

Pyrochroite Crystallography

Axial Ratios:

a:c = 1:1.40119

Cell Dimensions:

a = 3.34, c = 4.68, Z = 1; V = 45.21 Den(Calc)= 3.27

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: P 3m1

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

By Intensity(I/I_o): 2.45(1), 4.72(0.9), 1.826(0.6),

Forms:

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Forms: ( 3 0 2) ( 9 0 4) ( 1 1 0) ( 1 0 1) ( 0 0 1)

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Crystal Structure:

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Parise J B , Theroux B , Li R , Loveday J S , Marshall W G , Klotz S , Physics and Chemistry of Minerals , 25 (1998) p.130-137, Pressure dependence of hydrogen bonding in metal deuteroxides:, a neutron powder diffraction study of Mn(OD)2 and beta-Co(OD)2., Sample: P = 0.0 GPa

View Additional jPOWD Structure files for Pyrochroite
[1] [2] [3] [4] [5]

Physical Properties of Pyrochroite

Cleavage:

{0001} Perfect

Color:

Colorless, White, Pale green, Blue, Dark brown.

Density:

3.26

Diaphaneity:

Subtranslucent to opaque

Fracture:

Flexible - Flexible fragments.

Habit:

Foliated - Two dimensional platy forms.

Hardness:

2.5-3 - Finger Nail-Calcite

Luminescence:

Non-fluorescent.

Luster:

Adamantine

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Pyrochroite

Gladstone-Dale:

CI meas= 0.048 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.051 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2144,KPDmeas= 0.215,KC= 0.226
Ncalc = 1.74

Optical Data:

Uniaxial (-), e=1.72-1.723, w=1.68-1.681, bire=0.0400-0.0420.

Calculated Properties of Pyrochroite

Electron Density:

Bulk Density (Electron Density)=3.15 gm/cc
note: Specific Gravity of Pyrochroite =3.26 gm/cc.

Fermion Index:

Fermion Index = 0.0001760689
Boson Index = 0.9998239311

Photoelectric:

PE_Pyrochroite= 15.83 barns/electron
U=PE_Pyrochroite x rElectron Density= 49.90 barns/cc.

Radioactivity:

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

Pyrochroite Classification

Dana Class:

06.02.01.03 (06)Hydroxides and Oxides Containing Hydroxyl

(06.02)where X++ (OH)2

(06.02.01)Brucite group (Rhombohedral: P-3m1)

06.02.01.01 Brucite Mg(OH)2 P 3m1 3 2/m

06.02.01.02 Amakinite (Fe,Mg)(OH)2 P 3m1 3 2/m

06.02.01.03 Pyrochroite Mn(OH)2 P 3m1 3 2/m

06.02.01.04 Portlandite Ca(OH)2 P 3m1 3 2/m

06.02.01.05 Theophrastite Ni(OH)2 P 3m1 3 2/m

Strunz Class:

04.FE.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.F - Hydroxides (without V or U)

04.FE -Hydroxides with OH, without H2O; sheets of edge-sharing octahedra

04.FE.05 Amakinite (Fe,Mg)(OH)2 P 3m1 3 2/m

04.FE.05 Brucite Mg(OH)2 P 3m1 3 2/m

04.FE.05 Portlandite Ca(OH)2 P 3m1 3 2/m

04.FE.05 Pyrochroite Mn(OH)2 P 3m1 3 2/m

04.FE.05 Theophrastite Ni(OH)2 P 3m1 3 2/m

04.FE.05 Fougerite! (Fe,Mg)6Fe2(OH)18•4(H2O) R 3m 3 2/m

Other Pyrochroite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Pyrochroite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - Franklin Minerals(Palache)
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - HyperPhysics
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - WWW-MINCRYST

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Pyrochroite

Mn(OH)2
Dana No: 06.02.01.03 Strunz No: 04.FE.05
Locality:

Notes: