Pecoraite Mineral Data

General Pecoraite Information

Chemical Formula:

Ni3Si2O5(OH)4

Composition:

Molecular Weight = 380.27 gm

Silicon 14.77 % Si 31.60 % SiO₂

Nickel 46.30 % Ni 58.92 % NiO

Hydrogen 1.06 % H 9.48 % H₂O

Oxygen 37.87 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ni₃SI₂O₅(OH)₄

Environment:

Formed by weathering of Ni-Fe meteorite fragments in a desert environment.

IMA Status:

Approved IMA 1969

Locality:

In the Wolf Creek meteorite. Link to MinDat.org Location Data.

Name Origin:

Named for William Thomas Pecora (1913-1972), Director of the U.S. Geological Survey, geologist and student of nickel silicate deposits.

Name Pronunciation:

Pecoraite + Pronunciation

Synonym:

Chrysotile - (Ni bearing)

Pecoraite Image

Images:

Pecoraite

Comments: Dark green massive pecoraite in matrix.
Location: Nullagin, Western Australia, Australia. Scale: Specimen Size 2x2.5 cm.
© Diederik Visser

Pecoraite Crystallography

Axial Ratios:

a:b:c =0.5742:1:1.6048

Cell Dimensions:

a = 5.26, b = 9.16, c = 14.7, Z = 4; beta = 92° V = 707.84 Den(Calc)= 3.57

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m

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

By Intensity(I/I_o): 7.43(1), 1.529(0.8), 3.66(0.8),

Physical Properties of Pecoraite

Color:

Dark green.

Density:

3.84 - 3.084, Average = 3.46

Diaphaneity:

Translucent

Hardness:

2.5 - Finger Nail

Streak:

light green

Optical Properties of Pecoraite

Gladstone-Dale:

CI meas= 0.173 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.198 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1618,KPDmeas= 0.1669,KC= 0.2017
Ncalc = 1.62 - 1.77

Optical Data:

Biaxial (+/-), a=1.565, b=1.565-1.603, g=1.565-1.603, bire=0.0000-0.0380, 2V(Calc)=0, 2V(Meas)=0.

Calculated Properties of Pecoraite

Electron Density:

Bulk Density (Electron Density)=3.42 gm/cc
note: Specific Gravity of Pecoraite =3.46 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Pecoraite= 18.77 barns/electron
U=PE_Pecoraite x rElectron Density= 64.27 barns/cc.

Radioactivity:

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

Pecoraite Classification

Dana Class:

71.01.02d.04 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.01)with 1:1 layers

(71.01.02d)Serpentine group (Chrysotile subgroup)

71.01.02d.00 Chrysotile! Mg3Si2O5(OH)4 A2/m 2/m

71.01.02d.01 Clinochrysotile? Mg3Si2O5(OH)4 Cc, C 2/m Mono

71.01.02d.02 Orthochrysotile? Mg3Si2O5(OH)4 Unk Ortho

71.01.02d.03 Parachrysotile? Mg3Si2O5(OH)4 Unk Ortho

71.01.02d.04 Pecoraite Ni3Si2O5(OH)4 C 2/m 2/m

Strunz Class:

09.ED.15 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.ED -Phyllosilicates with kaolinite layers

09.ED.15 Clinochrysotile? Mg3Si2O5(OH)4 Cc, C 2/m Mono

09.ED.15 Berthierine (Fe,Fe,Al,Mg)2-3(Si,Al)2O5(OH)4 Cm m

09.ED.15 Brindleyite (Ni,Mg,Fe)2Al(SiAl)O5(OH)4 C 2 2

09.ED.15 Amesite Mg2Al(SiAl)O5(OH)4 C1 1

09.ED.15 Antigorite (Mg,Fe)3Si2O5(OH)4 Cm m

09.ED.15 Caryopilite (Mn,Mg,Zn,Fe)3(Si,As)2O510(OH,Cl)4 Cm or C 2/m Mono

09.ED.15 Fraipontite (Zn,Al)3(Si,Al)2O5(OH)4 Cm m

09.ED.15 Cronstedtite Fe2Fe(SiFe)O5(OH)4 P 3₁m 3m

09.ED.15 Chrysotile Mg3Si2O5(OH)4 A2/m 2/m

09.ED.15 Nepouite Ni3Si2O5(OH)4 Ccm21 mm2

09.ED.15 Greenalite (Fe,Fe)2-3Si2O5(OH)4 Unk Mono

09.ED.15 Kellyite (Mn,Mg,Al)3(Si,Al)2O5(OH)4 P 6₃ 6

09.ED.15 Maufite? (Mg,Ni)Al4Si3O13•4(H2O)(?) Mono ? Mono

09.ED.15 Lizardite Mg3Si2O5(OH)4 P1 1

09.ED.15 Orthochrysotile? Mg3Si2O5(OH)4 Unk Ortho

09.ED.15 Manandonite Li2Al4[(Si2AlB)O10](OH)8 C1 1

09.ED.15 Pecoraite Ni3Si2O5(OH)4 C 2/m 2/m

09.ED.15 Parachrysotile? Mg3Si2O5(OH)4 Unk Ortho

Other Pecoraite 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 Pecoraite :
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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Print or Cut-and-Paste your Pecoraite Specimen Label here :

Pecoraite

Ni3Si2O5(OH)4
Dana No: 71.01.02d.04 Strunz No: 09.ED.15
Locality:

Notes:

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