Petewilliamsite Mineral Data

General Petewilliamsite Information

Chemical Formula:

(Ni,Co,Cu)30(As2O7)15

Composition:

Molecular Weight = 5,730.36 gm

Calcium 0.12 % Ca 0.17 % CaO

Iron 0.03 % Fe 0.04 % FeO

Cobalt 14.21 % Co 18.07 % CoO

Copper 2.67 % Cu 3.35 % CuO

Nickel 15.01 % Ni 19.11 % NiO

Arsenic 38.64 % As 59.26 % As₂O₅

Oxygen 29.32 % O

______ ______

100.00 % 99.99 % = TOTAL OXIDE

Empirical Formula:

Ni_14.66Co_13.82Cu_2.41Ca_0.17Fe²⁺_0.0315(As_1.97)15(O₇)

Environment:

In a fine-grained quartz specimen. It is the only known natural pyroarsenate.

IMA Status:

Approved IMA 2004 (Dana # Added)

Locality:

Johanngeorgenstadt, Saxony, Germany. Link to MinDat.org Location Data.

Name Origin:

Named for Peter (Pete) Allan Williams (b. 1950), Professor, Minerals and Materials Group, School of Science, Food and Horticulture, University of Western Sydney, Penrith South DC, N ew South Wales, Australia.

Synonym:

IMA2002-059

Petewilliamsite Image

Images:

Petewilliamsite

Comments: SEM image of a portion of a petewilliamsite aggregate. Note the rounded nature of the crystal faces. (Min. Mag. 68:235).
Location: Johanngeorgenstadt, Saxony, Germany. Scale: See Image.
© Mineralogical Magazine

Petewilliamsite Crystallography

Axial Ratios:

a:b:c =3.9208:1:1.6731

Cell Dimensions:

a = 33.256, b = 8.4818, c = 14.191, Z = 1; beta = 104.145° V = 3,881.50 Den(Calc)= 2.45

Crystal System:

Monoclinic - Sphenoidal H-M Symbol (2) Space Group: C 2

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

By Intensity(I/I_o): 3.118(1)(513,023), 3.005(0.6)(10.0.3), 1.637(0.5)(536),2.567(0.5)(10.2.0), 1.507(0.3)(553,15.3.3,204.235(0.3)(020),

Physical Properties of Petewilliamsite

Cleavage:

None

Color:

Dark violet red, Dark brownish red.

Diaphaneity:

Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Hardness:

1.5-2.5 - Hardness very near Gypsum

Luster:

Vitreous - Adamantine

Streak:

pale reddish brown

Optical Properties of Petewilliamsite

Optical Data:

NCalc= 1.41 - from Gladstone-Dale relationship (KC = 0.1681) where Ncalc=Dcalc*KC+1

RL Anisotrophism:

Not obvious.

RL Bireflectance:

None.

RL Color:

Dark gray with orange internal reflections.

RL Pleochroism:

None.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Petewilliamsite in Air**
λ	R	∑ R(λ)
400 nm	9.84
420 nm	9.85
440 nm	9.71
460 nm	9.63
470 nm	9.59
480 nm	9.55
500 nm	9.49
520 nm	9.39
540 nm	9.33
546 nm	9.32
560 nm	9.29
580 nm	9.33
589 nm	9.27
600 nm	9.33
620 nm	9.29
640 nm	9.33
650 nm	9.33
660 nm	9.32
680 nm	9.31
700 nm	9.30

**Calculated Relative Intensity Colors of Petewilliamsite in Air**
Relative Intensity	0%	100%	200%	300%	400%	500%	600%	700%	800%	900%	940%
R

Calculated Properties of Petewilliamsite

Electron Density:

Bulk Density (Electron Density)=2.29 gm/cc
note: Specific Gravity of Petewilliamsite =2.45 gm/cc.

Fermion Index:

Fermion Index = 0.0018451825
Boson Index = 0.9981548175

Photoelectric:

PE_{Petewilliamsite}= 39.26 barns/electron
U=PE_{Petewilliamsite} x rElectron Density= 89.74 barns/cc.

Radioactivity:

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

Petewilliamsite Classification

Dana Class:

38.04.13.01 (38)Anhydrous Phosphates, etc

(38.04)A+ XO4

(38.04.13)Dana Group

38.04.13.01 Petewilliamsite! (Ni,Co,Cu)30(As2O7)15 C 2 2

Strunz Class:

08.FA.25 08 - PHOSPHATES, ARSENATES, VANADATES

08.F - Polyphosphates, Polyarsenates, [4]-Polyvanadates

08.FA -Polyphosphates, etc., without OH and H2O; dimers of corner-sharing RO4 tetrahedra.

08.FA.25 Petewilliamsite! (Ni,Co,Cu)30(As2O7)15 C 2 2

Other Petewilliamsite Information

References:

NAME( CanMin, 42:1922) PHYS. PROP.(CanMin, 42:1922) OPTIC PROP.(MinMag, 68:235)

See Also:

Links to other databases for Petewilliamsite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Petewilliamsite

(Ni,Co,Cu)30(As2O7)15
Dana No: 38.04.13.01 Strunz No: 08.FA.25
Locality:

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