Johnsomervilleite Mineral Data

General Johnsomervilleite Information

Chemical Formula:

Na2Ca(Mg,Fe++,Mn)7(PO4)6

Composition:

Molecular Weight = 955.37 gm

Sodium 3.37 % Na 4.54 % Na₂O

Calcium 4.61 % Ca 6.46 % CaO

Magnesium 7.89 % Mg 13.08 % MgO

Manganese 4.03 % Mn 5.20 % MnO

Iron 20.46 % Fe 26.32 % FeO

Phosphorus 19.45 % P 44.57 % P₂O₅

Oxygen 40.19 % O

______ ______

100.00 % 100.17 % = TOTAL OXIDE

Empirical Formula:

Na_1.4Ca_1.1Fe²⁺_3.5Mg_3.1Mn²⁺_0.7(PO₄)₆

Environment:

Accessory mineral in podiform metamorphic segregations in kyanite-sillimanite-grade gneiss.

IMA Status:

Approved IMA 1980

Locality:

Glen Cosaidh, Loch Quoich,, Inverness-shire, Scotland. Link to MinDat.org Location Data.

Name Origin:

Named for John M. Somerville (1908-1978), who collected the first specimen.

Name Pronunciation:

Johnsomervilleite + Pronunciation

Johnsomervilleite Image

Images:

Johnsomervilleite

Comments: Dark brownish johnsomervilleite.
Location: Sapucaia Mine, Conselheiro Pena district, GalilÃ©ia, Governador Valadares, Rio Doce, Minas Gerais, Southeast Region, Brazil. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Johnsomervilleite Crystallography

Axial Ratios:

a:c = 1:2.84999

Cell Dimensions:

a = 15, c = 42.75, Z = 18; V = 8,330.08 Den(Calc)= 3.43

Crystal System:

Trigonal - RhombohedralH-M Symbol ( 3) Space Group: R 3

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

By Intensity(I/I_o): 2.764(1), 3.55(0.7), 3.7(0.7),

Physical Properties of Johnsomervilleite

Cleavage:

{0001} Perfect

Color:

Dark brown, Blackish gray.

Density:

3.35

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Splintery - Brittle fracture leaving splintery fragments.

Habit:

Colloform - Forming from a gel or colloidal mass.

Habit:

Dendritic - Branching "tree-like" growths of great complexity (e.g. pyrolusite).

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

light brown

Optical Properties of Johnsomervilleite

Gladstone-Dale:

CI meas= -0.031 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.007 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.191,KPDmeas= 0.1955,KC= 0.1896
Ncalc = 1.64 - 1.65

Optical Data:

Uniaxial (+/-), a=1.655, b=1.655, bire=0.0000.

Calculated Properties of Johnsomervilleite

Electron Density:

Bulk Density (Electron Density)=3.34 gm/cc
note: Specific Gravity of Johnsomervilleite =3.43 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Johnsomervilleite}= 8.87 barns/electron
U=PE_{Johnsomervilleite} x rElectron Density= 29.62 barns/cc.

Radioactivity:

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

Johnsomervilleite Classification

Dana Class:

38.02.05.02 (38)Anhydrous Phosphates, etc

(38.02)(A+ B++)5 (XO4)3

(38.02.05)Fillowite Group

38.02.05.01 Fillowite Na2Ca(Mn,Fe)7(PO4)6 R 3 3

38.02.05.02 Johnsomervilleite Na2Ca(Mg,Fe,Mn)7(PO4)6 R 3 3

38.02.05.03 Chladniite Na2Ca(Mg,Fe)7(PO4)6 R 3 3

38.02.05.04 Galileiite! NaFe4(PO4)3 R 3 3

38.02.05.05 Xenophyllite! Na4Fe7(PO4)6 P1 or P1 Tri

38.02.05.06 Stornesite-(Y)! (Y,Ca)[]2Na6(Ca,Na)8(Mg,Fe)43(PO4)36 R 3 3

Strunz Class:

08.AC.50 08 - PHOSPHATES, ARSENATES, VANADATES

08.A - Phosphates, etc. without additional anions, without H2O

08.AC -With medium-sized and large cations

08.AC.50 Fillowite Na2Ca(Mn,Fe)7(PO4)6 R 3 3

08.AC.50 Chladniite Na2Ca(Mg,Fe)7(PO4)6 R 3 3

08.AC.50 Johnsomervilleite Na2Ca(Mg,Fe,Mn)7(PO4)6 R 3 3

08.AC.50 Galileiite! NaFe4(PO4)3 R 3 3

08.AC.50 Stornesite-(Y)! (Y,Ca)[]2Na6(Ca,Na)8(Mg,Fe)43(PO4)36 R 3 3

08.AC.50 Xenophyllite! Na4Fe7(PO4)6 P1 or P1 Tri

Other Johnsomervilleite 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 Johnsomervilleite :
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

Search for Johnsomervilleite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Johnsomervilleite :

A Bijoux Google Search for Johnsomervilleite
Adam's Minerals Google Search for Johnsomervilleite
Cape Minerals Google Search for Johnsomervilleite
Dakota Matrix Minerals Google Search for Johnsomervilleite
Excalibur Mineral Corp. Google Search for Johnsomervilleite
Exceptional Minerals Google Search for Johnsomervilleite
John Betts Fine Minerals Search for Johnsomervilleite
McDougall Minerals Google Search for Johnsomervilleite
Mineral News Website Link
Rock and Mineral Shows Google Search for Johnsomervilleite
Weinrich Minerals, Inc. Google Search for Johnsomervilleite

Ask about Johnsomervilleite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Johnsomervilleite

Na2Ca(Mg,Fe++,Mn)7(PO4)6
Dana No: 38.02.05.02 Strunz No: 08.AC.50
Locality:

Notes: