Pyrochroite Mineral Data

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.

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

Diaphaniety:

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

Optical Data:

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

Calculated Properties of Pyrochroite

Electron Density:

r_electron=3.15 gm/cc
note: r_Pyrochroite=3.26 gm/cc.

Fermion Index

Fermion Index = 0.00017
Boson Index = 0.99983

Photoelectric:

PE_Pyrochroite= 15.83 barns/electron
U=PE_Pyrochroite x r_electron= 49.90 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Pyrochroite is Not Radioactive

Pyrochroite Classification

Dana Class:

6.2.1.3 (6)Hydroxides and Oxides Containing Hydroxyl

(6.2)where X++ (OH)2

(6.2.1)Brucite group (Rhombohedral: P3¯m1)

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

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

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

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

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

Strunz Class:

IV/F.03-30 IV - Oxides

IV/F - Hydroxides and oxidic hydrates, water-bearing oxides with layered structure

IV/F.03 - Brucite series

IV/F.03-10 Brucite Mg(OH)2 P 3m1 3 2/m

IV/F.03-20 Amakinite (Fe,Mg)(OH)2 P 3m1 3 2/m

IV/F.03-30 Pyrochroite Mn(OH)2 P 3m1 3 2/m

IV/F.03-40 Theophrastite Ni(OH)2 P 3m1 3 2/m

IV/F.03-50 Paraotwayite Ni(OH)2-x(SO4,CO3)0.5xx=.5 Pm m

IV/F.03-60 Sweetite Zn(OH)2 P 4₁2₁2,P 4₃2₁2 4 2 2

IV/F.03-70 Ashoverite Zn(OH)2 I 4₁/amd 4/m 2/m 2/m

IV/F.03-80 Wulfingite Zn(OH)2 P 2₁2₁2₁ 2 2 2

IV/F.03-90 Spertiniite Cu(OH)2 C mc2₁ mm2

IV/F.03-100 Portlandite Ca(OH)2 P 3m1 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 - Franklin Minerals(Dunn) 5 - Franklin Minerals(Palache) 6 -Google Images 7 -Google Scholar 8 - HyperPhysics 9 -MinDAT 10 -MinMax(Deutsch) 11 -MinMax(English) 12 -Mineralienatlas (Deutsch) 13 -QUT Mineral Atlas 14 - WWW-MINCRYST 15 -École des Mines de Paris

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Pyrochroite

Mn(OH)2
Dana No: 6.2.1.3 Strunz No: IV/F.03-30
Locality:

Notes: