Francoanellite Mineral Data

General Francoanellite Information

Chemical Formula:

H6(K,Na)3(Al,Fe+++)5(PO4)8•13(H2O)

Composition:

Molecular Weight = 1,242.49 gm

Potassium 4.72 % K 5.69 % K₂O

Sodium 2.78 % Na 3.74 % Na₂O

Aluminum 9.77 % Al 18.46 % Al₂O₃

Iron 2.25 % Fe 3.21 % Fe₂O₃

Phosphorus 19.94 % P 45.70 % P₂O₅

Hydrogen 2.60 % H 23.20 % H₂O

Oxygen 57.95 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

H₆K_1.5Na_1.5Al_4.5Fe³⁺_0.5(PO₄)₈•13(H₂O)

Environment:

Occurs at the contact of "terra rossa" with bat guano in the karst cave.

IMA Status:

Approved IMA 1976

Locality:

Grotte di Castellana, Puglia, Italy. Link to MinDat.org Location Data.

Name Origin:

Named for Franco Anelli, professor of geography, University of Bari, Italy, who discovered the cave in which the mineral was found.

Name Pronunciation:

Francoanellite + Pronunciation

Synonym:

ICSD 407357

PDF 29-980

Francoanellite Image

Images:

Francoanellite

Comments: Chalky massive francoanellite.
Location: Giottodi Castellana Cave, Puglia, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Francoanellite Crystallography

Axial Ratios:

a:c = 1:9.47187

Cell Dimensions:

a = 8.71, c = 82.5, Z = 6; V = 5,420.27 Den(Calc)= 2.28

Crystal System:

Trigonal Space Group: R 3c or R 3c

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

By Intensity(I/I_o): 13.83(1), 3.4(0.65), 2.799(0.62),

Physical Properties of Francoanellite

Color:

Yellowish white.

Density:

2.26

Habit:

Nodular - Tuberose forms having irregular protuberances over the surface.

Habit:

Pulverulent - Forms a loose, poorly-coherent powdery mass.

Hardness:

1-2 - Between Talc and Gypsum

Streak:

white

Optical Properties of Francoanellite

Gladstone-Dale:

CI meas= 0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.019 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2248,KPDmeas= 0.2268,KC= 0.2291
Ncalc = 1.52

Optical Data:

Uniaxial (+), w=1.51, e=1.515, bire=0.0050.

Calculated Properties of Francoanellite

Electron Density:

Bulk Density (Electron Density)=2.29 gm/cc
note: Specific Gravity of Francoanellite =2.26 gm/cc.

Fermion Index:

Fermion Index = 0.000764144
Boson Index = 0.999235856

Photoelectric:

PE_{Francoanellite}= 2.45 barns/electron
U=PE_{Francoanellite} x r_electron= 5.59 barns/cc.

Radioactivity:

GRapi = 68.89 (Gamma Ray American Petroleum Institute Units)
Concentration of Francoanellite per GRapi unit = 1.45 (%)

Estimated Radioactivity from Francoanellite - barely detectable

Francoanellite Classification

Dana Class:

39.03.05.02 (39)Hydrated Acid Phosphates, etc

(39.03)with miscellaneous formulae

(39.03.05)Dana Group

39.03.05.01 Hannayite (NH4)2Mg3H4(PO4)4•8(H2O) P1 1

39.03.05.02 Francoanellite H6(K,Na)3(Al,Fe)5(PO4)8•13(H2O) R 3c or R 3c Trig

Strunz Class:

08.CH.25 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CH -With large and medium-sized cations, RO4:H2O < 1:1

08.CH.25 Francoanellite H6(K,Na)3(Al,Fe)5(PO4)8•13(H2O) R 3c or R 3c Trig

08.CH.25 Taranakite K3Al5(HPO4)6(PO4)2•18(H2O) R 3c 3 2/m

Other Francoanellite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

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

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

Francoanellite

H6(K,Na)3(Al,Fe+++)5(PO4)8•13(H2O)
Dana No: 39.03.05.02 Strunz No: 08.CH.25
Locality:

Notes:

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