Bechererite Mineral Data

General Bechererite Information

Chemical Formula:

(Zn,Cu)6Zn2(OH)13[(S,Si)(O,OH)4]2

Composition:

Molecular Weight = 933.60 gm

Zinc 45.53 % Zn 56.67 % ZnO

Copper 10.21 % Cu 12.78 % CuO

Silicon 1.50 % Si 3.22 % SiO₂

Hydrogen 1.62 % H 14.47 % H₂O

Sulfur 5.15 % S 10.29 % SO₂

Oxygen 35.99 % O

______ ______

100.00 % 97.43 % = TOTAL OXIDE

Empirical Formula:

Zn_4.5Cu_1.5Zn₂(OH)₁₃2(S_0.75)2(Si_0.25)2(O₃)2(OH)

Environment:

Alteration product of copper and zinc orebodies.

IMA Status:

Approved IMA 1994 (Dana # Added)

Locality:

The dump of the Tonopah-Belmont mine, Osborne silver-gold district, Maricopa County, Arizona USA. Link to MinDat.org Location Data.

Name Origin:

Named after Dr. Karl Becherer (1926-) of the University of Vienna, in recognition of his contributions to the mineralogy of Spangolite from Lavrion.

Name Pronunciation:

Bechererite + Pronunciation

Synonym:

ICSD 81354

IMA1994-005

PDF 46-1438

Bechererite Crystallography

Axial Ratios:

a:c = 1:0.88632

Cell Dimensions:

a = 8.322, c = 7.376, Z = 1; V = 442.39 Den(Calc)= 3.50

Crystal System:

Trigonal - Pyramidal H-M Symbol (3) Space Group: P 3

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

By Intensity(I/I_o): 7.37(1), 2.556(0.5), 3.282(0.3),

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

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Physical Properties of Bechererite

Cleavage:

{001} Perfect

Color:

Light green.

Density:

3.45 - 3.49, Average = 3.47

Diaphaneity:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces.

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

2.5-3 - Finger Nail-Calcite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Bechererite

Dichroism (e):

colorless.

Dichroism (w):

colorless.

Gladstone-Dale:

CI meas= 0.023 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.032 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.188,KPDmeas= 0.1896,KC= 0.1941
Ncalc = 1.67 - 1.68

Optical Data:

Uniaxial (-), e=1.611, w=1.705, bire=0.0940.

Calculated Properties of Bechererite

Electron Density:

Bulk Density (Electron Density)=3.36 gm/cc
note: Specific Gravity of Bechererite =3.47 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Bechererite= 27.31 barns/electron
U=PE_Bechererite x rElectron Density= 91.87 barns/cc.

Radioactivity:

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

Bechererite Classification

Dana Class:

31.01.06.02 (31)Hydrated Sulfates Containing Hydroxyl or Halogen

(31.01)where (A+ B++)m (XO4)p Zqï¿½x(H2O), where m:p>6:1

(31.01.06)Schulenbergite group

31.01.06.01 Schulenbergite (Cu,Zn)7(SO4,CO3)2(OH)10•3(H2O) Hex Hex

31.01.06.02 Bechererite! (Zn,Cu)6Zn2(OH)13[(S,Si)(O,OH)4]2 P 3 3

31.01.06.03 Osakaite! Zn4SO4(OH)6•5H2O P1 1

31.01.06.04 Zn-Schulenbergite! (Zn,Cu)7(SO4,CO3)2(OH)10•3(H2O) Hex Hex

Strunz Class:

07.DD.55 07 - SULFATES (SELENATES, TELLURATES)

07.D - Sulfates (selenates, etc.) with additional anions, with H2O

07.DD -With only medium-sized cations; sheets of edge-sharing octahedra

07.DD.55 Bechererite! (Zn,Cu)6Zn2(OH)13[(S,Si)(O,OH)4]2 P 3 3

Other Bechererite Information

References:

NAME( MinRec) PHYS. PROP.(Am.Min.,Vol.81,1996) OPTIC PROP.(MinRec)

See Also:

Links to other databases for Bechererite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info
13 - WWW-MINCRYST

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Print or Cut-and-Paste your Bechererite Specimen Label here :

Bechererite

(Zn,Cu)6Zn2(OH)13[(S,Si)(O,OH)4]2
Dana No: 31.01.06.02 Strunz No: 07.DD.55
Locality:

Notes:

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