Birchite Mineral Data

General Birchite Information

Chemical Formula:

Cd2Cu2(PO4)2(SO4)•5H2O

Composition:

Molecular Weight = 741.06 gm

Calcium 0.11 % Ca 0.15 % CaO

Manganese 0.15 % Mn 0.19 % MnO

Zinc 0.88 % Zn 1.10 % ZnO

Cadmium 31.70 % Cd 36.22 % CdO

Copper 16.64 % Cu 20.82 % CuO

Phosphorus 8.65 % P 19.82 % P₂O₅

Hydrogen 1.36 % H 12.16 % H₂O

Sulfur 3.81 % S 9.51 % SO₃

Oxygen 36.70 % O

______ ______

100.00 % 99.97 % = TOTAL OXIDE

Empirical Formula:

Cu_1.94P_2.07S_0.88O₁₂•5(H₂O)Zn_0.1Cd_2.09Ca_0.02Mn²⁺_0.02

Environment:

Late-stage supergene mineral formed as part of a suite of secondary phosphate minerals under low-temperature conditions. New structure type.

IMA Status:

Approved IMA 2006 (Dana # Added)

Locality:

Block 14 Opencut, Broken Hill, New South Wales, Australia Link to MinDat.org Location Data.

Name Origin:

Named for William D. Birch, Senior Curator of Geosciences at Museum Victoria, Australia, in recognition of his contribution to Australian geological sciences.

Synonym:

IMA2006-048

Birchite Image

Images:

Birchite

Comments: SEM image showing bladed crystals of birchite on anglesite. The crystals are flattened on (100) and show the principal forms {100}, {010}, and {101}. (AmMin, v93:912).
Location: Block 14 Opencut, Broken Hill, New South Wales, Australia. Scale: Scale Bar 50µm.
© American Mineralogist

Birchite Crystallography

Axial Ratios:

a:b:c =0.5018:1:0.2944

Cell Dimensions:

a = 10.489, b = 20.901, c = 6.155, Z = 4; V = 1,349.36 Den(Calc)= 3.65

Crystal System:

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

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

By Intensity(I/I_o): 10.451(1)(020), 1.919(0.8)(432), 2.902(0.7)(260),3.484(0.39)(060), 4.223(0.38)(131), 2.719(0.33)(132), 2.652(0.32)(042), 5.146(0.28)(111),

Physical Properties of Birchite

Color:

Pale blue.

Density:

3.61

Diaphaneity:

Translucent to transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Birchite

Gladstone-Dale:

CI meas= 0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.018 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1762,KPDmeas= 0.1781,KC= 0.1793
Ncalc = 1.65

Optical Data:

Biaxial (+), a=1.624, b=1.636, g=1.669, bire=0.0450

Calculated Properties of Birchite

Electron Density:

Bulk Density (Electron Density)=3.43 gm/cc
note: Specific Gravity of Birchite =3.61 gm/cc.

Fermion Index:

Fermion Index = 0.08
Boson Index = 0.92

Photoelectric:

PE_Birchite= 89.11 barns/electron
U=PE_Birchite x rElectron Density= 305.26 barns/cc.

Radioactivity:

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

Birchite Classification

Dana Class:

43.05.12.02 (43)Compound Phosphates, etc.

(43.05)(Hydrated Compound Anions With Hydroxyl or Halogen)

(43.05.12)Synadelphite Group

43.05.12.01 Synadelphite (Mn,Mg,Ca,Pb)9(AsO3)(AsO4)2(OH)9•2(H2O)(?) P nma 2/m 2/m 2/m

43.05.12.02 Birchite! Cd2Cu2(PO4)2(SO4)•5H2O P nma 2/m 2/m 2/m

Strunz Class:

08.DB.70 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DB -With only medium-sized cations, (OH, etc.):RO4 < 1:1

08.DB.70 Birchite! Cd2Cu2(PO4)2(SO4)•5H2O P nma 2/m 2/m 2/m

Other Birchite Information

References:

NAME( AmMin, v93:910) PHYS. PROP.(AmMin, v93:910) OPTIC PROP.(AmMin, v93:910)

See Also:

Links to other databases for Birchite :
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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Print or Cut-and-Paste your Birchite Specimen Label here :

Birchite

Cd2Cu2(PO4)2(SO4)•5H2O
Dana No: 43.05.12.02 Strunz No: 08.DB.70
Locality:

Notes:

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