Arrojadite Mineral Data

General Arrojadite Information

Chemical Formula:

KNa4CaMn++4Fe++10Al(PO4)12(OH,F)2

Composition:

Molecular Weight = 2,151.01 gm

Potassium 1.82 % K 2.19 % K₂O

Sodium 4.28 % Na 5.76 % Na₂O

Calcium 1.86 % Ca 2.61 % CaO

Manganese 10.22 % Mn 13.19 % MnO

Aluminum 1.25 % Al 2.37 % Al₂O₃

Iron 25.96 % Fe 33.40 % FeO

Phosphorus 17.28 % P 39.59 % P₂O₅

Hydrogen 0.07 % H 0.63 % H₂O

Oxygen 36.82 % O

Fluorine 0.44 % F 0.44 % F

- % F -0.19 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

KNa₄CaMn²⁺₄Fe²⁺₁₀Al(PO₄)₁₂(OH)_1.5F_0.5

Environment:

Occurs at a high temperature (approx. 800 degrees C) primary mineral in granite pegmatites. Now is the series name.

IMA Status:

Renamed IMA 2005, Dana # changed from 41.7.2.1

Locality:

In Brazil, from the Sierra Branca pegmatite, 13 km south of Pedra Lavrada, Picui, Paraiba; in the Enio pegmatite mine, northeast of Galileia, and the Sapucaia pegmatite mine, about 50 Link to MinDat.org Location Data.

Name Origin:

To honor Miguel Arrojado Ribeiro Lisboa (1872-1932), Brazilian geologist. Arrojadite {1925) is renamed arrojadite-(KFe) and arrojadite becomes the group name.

Name Pronunciation:

Arrojadite + Pronunciation

Synonym:

ICSD 100872

PDF 34-149

Arrojadite Image

Images:

Arrojadite

Comments: Brownish to clear crystals of arrojadite on matrix.
Location: Big Fish river area, Yukon Territory, Canada. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Arrojadite

Comments: Tabular, diamond shaped golden yellow crystal of arrojadite.
Location: Rapid Creek, Yukon, Canada. Scale: Crystal to 5mm..
© Tom Loomis / Dakota Matrix

Arrojadite Crystallography

Axial Ratios:

a:b:c =1.6444:1:2.4612

Cell Dimensions:

a = 16.537, b = 10.056, c = 24.75, Z = 4; beta = 105.65° V = 3,963.24 Den(Calc)= 3.60

Crystal System:

Monoclinic - Domatic H-M Symbol (m) Space Group: Cc

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

By Intensity(I/I_o): 3.042(1), 2.714(0.85), 3.222(0.45),

Physical Properties of Arrojadite

Cleavage:

{001} Distinct

Color:

Olive green, Clove brown, Yellow.

Density:

3.56

Diaphaneity:

Translucent

Fracture:

Conchoidal - Uneven - Uneven fracture producing small, conchoidal fragments.

Hardness:

5 - Apatite

Luster:

Vitreous - Greasy

Streak:

green gray

Optical Properties of Arrojadite

Gladstone-Dale:

CI meas= 0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.186,KPDmeas= 0.1881,KC= 0.1892
Ncalc = 1.67 - 1.68

Optical Data:

Biaxial (+), a=1.664, b=1.67, g=1.675, bire=0.0110, 2V(Calc)=84, 2V(Meas)=86.

Calculated Properties of Arrojadite

Electron Density:

Bulk Density (Electron Density)=3.44 gm/cc
note: Specific Gravity of Arrojadite =3.56 gm/cc.

Fermion Index:

Fermion Index = 0.0057083688
Boson Index = 0.9942916312

Photoelectric:

PE_Arrojadite= 11.79 barns/electron
U=PE_Arrojadite x r_electron= 40.52 barns/cc.

Radioactivity:

GRapi = 25.32 (Gamma Ray American Petroleum Institute Units)
Concentration of Arrojadite per GRapi unit = 3.95 (%)

Estimated Radioactivity from Arrojadite - barely detectable

Arrojadite Classification

Dana Class:

41.07.02a.00 (41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen

(41.07)where (A B)m (XO4)4 Zq

(41.07.02a)Arrojadite Group (Arrojadite Subgroup) (Al in Al site, OH in W site, Fe in M site)

41.07.02a.00 Arrojadite! KNa4CaMn4Fe10Al(PO4)12(OH,F)2 Cc m

41.07.02a.01 Arrojadite-(KNa)! KNa4Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

41.07.02a.02 Arrojadite-(KFe)! KNa2CaNa2(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

41.07.02a.03 Arrojadite-(NaFe)! NaNa2CaNa2(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

41.07.02a.04 Arrojadite-(BaNa)! BaFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

41.07.02a.05 Arrojadite-(BaFe)! (Ba,K,Pb)Na3(Ca,Sr)(Fe,Mg,Mn)14Al(PO4)11(PO3OH)(OH,F)2 Cc m

41.07.02a.06 Arrojadite-(SrFe)! SrFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

41.07.02a.07 Arrojadite-(PbFe)! PbFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

Strunz Class:

08.BF.05 08 - PHOSPHATES, ARSENATES, VANADATES

08.B - Phosphates, etc. with Additional Anions, without H2O

08.BF -With medium-sized and large cations, (OH, etc.):RO4 < 0.5:1

08.BF.05 Arrojadite! KNa4CaMn4Fe10Al(PO4)12(OH,F)2 Cc m

08.BF.05 Dickinsonite! KNa4Ca(Mn,Fe)14Al(PO4)12(OH)2 Cc m

08.BF.05 Arrojadite-(BaFe)! (Ba,K,Pb)Na3(Ca,Sr)(Fe,Mg,Mn)14Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Arrojadite-(KFe)! KNa2CaNa2(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Arrojadite-(NaFe)! NaNa2CaNa2(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Arrojadite-(SrFe)! SrFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Arrojadite-(KNa)! KNa4Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Dickinsonite-(KNa)! KNa4Ca(Mn,Fe,Mg)13Al(PO4)11(PO4)(OH,F)2 Cc m

08.BF.05 Arrojadite-(PbFe)! PbFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Fluorarrojadite-(BaNa)! BaFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(F,OH)2 Cc m

08.BF.05 Arrojadite-(BaNa)! BaFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(OH,F)2 Cc m

08.BF.05 Fluorarrojadite-(KNa)! KNa4Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(F,OH)2 Cc m

08.BF.05 Fluorarrojadite-(BaFe)! (Ba,K,Pb)Na3(Ca,Sr)(Fe,Mg,Mn)14Al(PO4)11(PO3OH)(F,OH)2 Cc m

08.BF.05 Ferri-arrojadite-(BaNa)! BaFeNa2Ca(Fe,Mn,Mg)13Al(PO4)11(PO3OH)(F,OH)2 Cc m

08.BF.05 Dickinsonite-(KMnNa)! KNaMnNa3Ca(Mn,Fe,Mg)13Al(PO4)11(PO4)(OH,F)2 Cc m

08.BF.05 Dickinsonite-(KNaNa)! KNaNa4Ca(Mn,Fe,Mg)13Al(PO4)11(PO4)(OH,F)2 Cc m

08.BF.05 Dickinsonite-(NaNa)! Na2Na4Ca(Mn,Fe,Mg)13Al(PO4)11(PO4)(OH,F)2 Cc m

Other Arrojadite Information

References:

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

See Also:

Links to other databases for Arrojadite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - CalTech Mineral Spectroscopy
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST

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Arrojadite

KNa4CaMn++4Fe++10Al(PO4)12(OH,F)2
Dana No: 41.07.02a.00 Strunz No: 08.BF.05
Locality:

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