Lukrahnite Mineral Data

Lukrahnite Mineral Data

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General Lukrahnite Information

Chemical Formula:

Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2

Composition:

Molecular Weight = 468.74 gm

Calcium 8.55 % Ca 11.96 % CaO

Zinc 6.98 % Zn 8.68 % ZnO

Iron 9.53 % Fe 13.63 % Fe₂O₃

Copper 8.13 % Cu 9.16 % Cu₂O

Arsenic 31.97 % As 49.03 % As₂O₅

Hydrogen 0.71 % H 6.34 % H₂O

Oxygen 34.13 % O

______ ______

100.00 % 98.81 % = TOTAL OXIDE

Empirical Formula:

CaCu_0.6Zn_0.5Fe³⁺_0.8(AsO₄)₂(H₂O)_1.3(OH)_0.7

Environment:

Ca analog of gartrellite. Tsumcorite group

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Tsumeb mine, Namibia. Link to MinDat.org Location Data.

Name Origin:

Named for Ludger Krahn (1957-), Geologischer Dienst Nordrhein-Westfalen, geologist who provided the initial specimen for study.

Synonym:

IMA1999-030

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Lukrahnite Crystallography

Axial Ratios:

a:b:c =0.9851:1:1.3358

Cell Dimensions:

a = 5.457, b = 5.539, c = 7.399, Z = 1; alpha = 68.43°, beta = 68.9°, gamma = 69.44° V = 181.68 Den(Calc)= 4.28

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 3.416(1)(112), 2.927(0.64)(111), 3.186(0.4)(012,102),2.533(0.3)(201,212), 2.7(0.3)(211), 2.832(0.26), 2.468(0.25), 4.953(0.22),

Physical Properties of Lukrahnite

Cleavage:

None

Color:

Yellow.

Diaphaniety:

Transparent

Fracture:

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

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

5 - Apatite

Luster:

Vitreous - Adamantine

Streak:

light yellow

Optical Properties of Lukrahnite

Gladstone-Dale:

CI calc= 0.026 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1989,KC= 0.2042

Optical Data:

Biaxial (+), a=1.83, b=1.834, g=1.89, bire=0.0600

Calculated Properties of Lukrahnite

Electron Density:

r_electron=4.06 gm/cc
note: r_Lukrahnite=4.28 gm/cc.

Fermion Index

Fermion Index = 0.00516
Boson Index = 0.99484

Photoelectric:

PE_Lukrahnite= 32.96 barns/electron
U=PE_Lukrahnite x r_electron= 133.93 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Lukrahnite is Not Radioactive

Lukrahnite Classification

Dana Class:

43.2.2.3 (43)Compound Phosphates, etc.

(43.2)(Anhydrous Normal Compound Anions)

(43.2.2)Dana Group

43.2.2.1 Gartrellite Pb(Cu,Fe)2(AsO4,SO4)2(CO3,H2O)0.7 P1,P 1 Tri

43.2.2.2 Zincgartrellite! Pb(Zn,Fe,Cu)2(AsO4)2(OH,H2O)2 P1 1

43.2.2.3 Lukrahnite ! Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2 P1 1

Strunz Class:

VII/C.31-78 VII - Phosphates, Arsenates and Vanadates

VII/C - Water-bearing phosphates without unfamiliar anions, cations of medium and big size: Fe, Mn, Zn, Mg and Ca, (NH4)1+

VII/C.31 - Mawbyite - Gartrellite series

VII/C.31-02 Schneebergite! Bi(Co,Ni)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-04 Nickelschneebergite! Bi(Ni,Co)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-05 Mawbyite Pb(FeZn)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-06 Cabalzarite! Ca(Mg,Al,Fe)2(AsO4)2(H2O,OH)2 C 2/m 2/m

VII/C.31-08 Nickellotharmeyerite! Ca(Ni,Fe,Co)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-10 Ferrilotharmeyerite Ca(Zn,Cu)(Fe,Zn)(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-20 Lotharmeyerite CaZnMn(AsO3OH)4(OH)3 C 2/m,C 2,Cm Mono

VII/C.31-30 Manganlotharmeyerite! Ca(Mn,Mg,)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-35 Cobaltlotharmeyerite! Ca(Co,Fe,Ni)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-36 Cobalttsumcorite! Pb(Co,Fe)2(AsO4)2(OH,H2O)2 C 2/m 2/m

VII/C.31-40 Thometzekite Pb(Cu,Zn)2(AsO4)2·2(H2O) C 2/m 2/m

VII/C.31-50 Tsumcorite PbZnFe(AsO4)2·(H2O) C 2/m 2/m

VII/C.31-74 Krettnichite! PbMn2(VO4)2(OH)2 C 2/m 2/m

VII/C.31-78 Lukrahnite Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2 P1 1

VII/C.31-80 Phosphogartrellite! PbCuFe(PO4)2(OH,H2O)2 P1 1

VII/C.31-90 Gartrellite Pb(Cu,Fe)2(AsO4,SO4)2(CO3,H2O)0.7 P1,P 1 Tri

VII/C.31-92 Zincgartrellite! Pb(Zn,Fe,Cu)2(AsO4)2(OH,H2O)2 P1 1

VII/C.31-98 Rappoldite! Pb(Co,Ni,Zn,)2(AsO4)2·2(H2O) P1 1

VII/C.31-100 Helmutwinklerite PbZn2(AsO4)2·2(H2O) P1 1

Other Lukrahnite Information

References:

NAME( AmMin, Vol 87, p 766) PHYS. PROP.(AmMin, Vol 87, p 766) OPTIC PROP.(AmMin, Vol 87, p 766)

See Also:

Links to other databases for Lukrahnite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 -Google Images 4 -Google Scholar 5 -Handbook of Mineralogy (UofA) 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas

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

Lukrahnite

Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2
Dana No: 43.2.2.3 Strunz No: VII/C.31-78
Locality:

Notes: