Donpeacorite Mineral Data

General Donpeacorite Information

Chemical Formula:

(Mn,Mg)MgSi2O6

Composition:

Molecular Weight = 223.75 gm

Magnesium 13.58 % Mg 22.52 % MgO

Manganese 18.41 % Mn 23.78 % MnO

Silicon 25.10 % Si 53.71 % SiO₂

Oxygen 42.90 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺_0.75Mg_1.25Si₂O₆

Environment:

In manganese-rich siliceous marbles metamorphosed to the upper amphibolite facies.

IMA Status:

Approved IMA 1984

Locality:

In the Balmat No. 4 mine, Balmat, St. Lawrence Co., New York, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Donald R. Peacor (1937- ), University of Michigan, Ann Arbor, Michigan, USA.

Name Pronunciation:

Donpeacorite + Pronunciation

Synonym:

ICSD 30676

PDF 38-358

Donpeacorite Image

Images:

Donpeacorite Braunite-I

Comments: Brown crystalline massive donpeacorite with dark brown black braunite.
Location: Zinc Corporation of America Mine #4, Balmat, Saint Lawrence County, New York, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Turneaureite Donpeacorite Parvowinchite

Comments: Colorless, transparent turneaureite masses with light brown tirodite (parvowinchite) and darker brown donpeacorite.
Location: 2500' level of the mine, ZCA Mine No. 4 (St Joe Mine; ZCA No. 4 mine), Balmat, Balmat-Edwards Zinc District, St Lawrence Co., New York, USA. Scale: Picture Size 0.5 cm.
© Jeff Weissman / Photographic Guide to Mineral Species

Donpeacorite Crystallography

Axial Ratios:

a:b:c =2.0707:1:0.5886

Cell Dimensions:

a = 18.384, b = 8.878, c = 5.226, Z = 8; V = 852.95 Den(Calc)= 3.48

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P bca

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

By Intensity(I/I_o): 3.18(1), 2.896(0.6), 4.03(0.1),

Physical Properties of Donpeacorite

Cleavage:

{110} Perfect

Color:

Yellow orange.

Density:

3.36

Diaphaneity:

Transparent to Translucent

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Vitreous (Glassy)

Optical Properties of Donpeacorite

Gladstone-Dale:

CI meas= 0 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.034 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1966,KPDmeas= 0.2037,KC= 0.2036
Ncalc = 1.68 - 1.71

Optical Data:

Biaxial (-), a=1.677, b=1.684, g=1.692, bire=0.0150, 2V(Calc)=88, 2V(Meas)=88.

Calculated Properties of Donpeacorite

Electron Density:

Bulk Density (Electron Density)=3.30 gm/cc
note: Specific Gravity of Donpeacorite =3.36 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Donpeacorite= 5.91 barns/electron
U=PE_Donpeacorite x rElectron Density= 19.49 barns/cc.

Radioactivity:

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

Donpeacorite Classification

Dana Class:

65.01.02.03 (65)Inosilicate Single-Width Unbranched Chains, W=1

(65.01)with chains P=2

(65.01.02)Orthopyroxenes

65.01.02.01 Enstatite Mg2Si2O6 P bca 2/m 2/m 2/m

65.01.02.02 Ferrosilite (Fe,Mg)2Si2O6 P bca 2/m 2/m 2/m

65.01.02.03 Donpeacorite (Mn,Mg)MgSi2O6 P bca 2/m 2/m 2/m

Strunz Class:

09.DA.05 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DA -Inosilicates with 2-periodic single chains, Si2O6; pyroxene family

09.DA.05 Donpeacorite (Mn,Mg)MgSi2O6 P bca 2/m 2/m 2/m

09.DA.05 Akimotoite! (Mg,Fe)SiO3 R 3 3

09.DA.05 Enstatite Mg2Si2O6 P bca 2/m 2/m 2/m

09.DA.05 Ferrosilite (Fe,Mg)2Si2O6 P bca 2/m 2/m 2/m

Other Donpeacorite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Donpeacorite :
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
15 - WWW-MINCRYST

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Donpeacorite

(Mn,Mg)MgSi2O6
Dana No: 65.01.02.03 Strunz No: 09.DA.05
Locality:

Notes:

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