Keckite Mineral Data

Keckite Mineral Data +

General Keckite Information

Chemical Formula:

Ca(Mn,Zn)2Fe+++3(PO4)4(OH)3·2(H2O)

Composition:

Molecular Weight = 770.34 gm

Calcium 4.16 % Ca 5.82 % CaO

Magnesium 0.32 % Mg 0.52 % MgO

Manganese 12.12 % Mn 15.65 % MnO

Zinc 1.70 % Zn 2.11 % ZnO

Iron 21.75 % Fe 31.10 % Fe₂O₃

Phosphorus 16.08 % P 36.85 % P₂O₅

Hydrogen 0.88 % H 7.83 % H₂O

Oxygen 42.99 % O

______ ______

100.00 % 99.90 % = TOTAL OXIDE

Empirical Formula:

Ca_0.8Mg_0.1Mn²⁺_1.7Zn_0.2Fe³⁺₃(PO₄)₄(OH)_2.7·2(H₂O)

Environment:

Weathering product of phosphate minerals in a complex granite pegmatite.

IMA Status:

Approved IMA 1979

Locality:

Hagendorf quarry, Bavaria, Germany. Link to MinDat.org Location Data.

Name Origin:

Named for Erich Keck, Etzenricht, Germany, collector of Hagendorf minerals.

Keckite Image

Images:

Keckite

Comments: Brown crystals of keckite on matrix.
Location: Hagendorf, Bavaria, Germany. Scale: .
© Lou Perloff / Photo Atlas of Minerals

Keckite Crystallography

Axial Ratios:

a:b:c =2.089:1:2.7454

Cell Dimensions:

a = 15.02, b = 7.19, c = 19.74, Z = 4; beta = 110.5° V = 1,996.80 Den(Calc)= 2.56

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 2.86(1), 9.3(0.8), 4.98(0.5),

Physical Properties of Keckite

Cleavage:

[001] Poor, [100] Indistinct

Color:

Brown, Gray brown, Yellow brown.

Density:

2.6

Diaphaniety:

Transparent to Translucent

Fracture:

Flexible - Flexible fragments.

Habit:

Fan Shaped - Occurs as radiating crystals shaped like a fan.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Earthy (Dull)

Streak:

yellow white

Optical Properties of Keckite

Gladstone-Dale:

CI meas= -0.117 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.134 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2717,KPDmeas= 0.2675,KC= 0.2395

Optical Data:

Biaxial (-), b=1.692, g=1.699,

Pleochroism (x):

reddish brown.

Pleochroism (y):

yellow.

Pleochroism (z):

paler yellow.

Calculated Properties of Keckite

Electron Density:

r_electron=2.54 gm/cc
note: r_Keckite=2.60 gm/cc.

Fermion Index

Fermion Index = 0.00588
Boson Index = 0.99412

Photoelectric:

PE_Keckite= 11.71 barns/electron
U=PE_Keckite x r_electron= 29.73 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Keckite is Not Radioactive

Keckite Classification

Dana Class:

42.11.4.1 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.4)Dana Group

42.11.4.1 Keckite Ca(Mn,Zn)2Fe3(PO4)4(OH)3·2(H2O) P 2₁/a 2/m

Strunz Class:

VII/D.29-80 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of very big and medium size: Al, Mg and Ca, Na, K

VII/D.29 - Whiteite - Jahnsite group

VII/D.29-10 Whiteite-(CaFeMg) Ca(Fe,Mn)Mg2Al2(PO4)4(OH)2·8(H2O) P 2₁/a 2/m

VII/D.29-20 Whiteite-(CaMnMg) CaMnMg2Al2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-30 Whiteite-(MnFeMg) (Mn,Ca)(Fe,Mn)Mg2Al2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-40 Rittmannite MnMnFeAl2(OH)2(PO4)4·8(H2O) P 2/a 2/m

VII/D.29-50 Jahnsite-(CaMnMg) CaMnMg2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-60 Jahnsite-(CaMnFe) CaMnFe2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-70 Jahnsite-(CaMnMn) CaMnMn2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-75 Jahnsite-(MnMnMn)* MnMnMn2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-80 Keckite Ca(Mn,Zn)2Fe3(PO4)4(OH)3·2(H2O) P 2₁/a 2/m

Other Keckite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic4)

See Also:

Links to other databases for Keckite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Keckite

Ca(Mn,Zn)2Fe+++3(PO4)4(OH)3·2(H2O)
Dana No: 42.11.4.1 Strunz No: VII/D.29-80
Locality:

Notes: