Fairfieldite Mineral Data

Fairfieldite Mineral Data +

General Fairfieldite Information

Chemical Formula:

Ca2(Mn,Fe++)(PO4)2·2(H2O)

Composition:

Molecular Weight = 361.29 gm

Calcium 22.19 % Ca 31.04 % CaO

Manganese 11.40 % Mn 14.73 % MnO

Iron 3.86 % Fe 4.97 % FeO

Phosphorus 17.15 % P 39.29 % P₂O₅

Hydrogen 1.12 % H 9.97 % H₂O

Oxygen 44.28 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂Mn²⁺_0.75Fe²⁺_0.25(PO₄)₂·2(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1879

Locality:

Branchville, Redding, Fairfield County, Connecticut, USA Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

ICSD 16017

PDF 10-390

Fairfieldite Image

Images:

Fairfieldite

Comments: Transparent, cockscomb druse of fairfieldite crystals.
Location: Foote mine, Kings Mountain, Cleveland County, North Carolina, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Fairfieldite Crystallography

Axial Ratios:

a:b:c =0.8797:1:0.834

Cell Dimensions:

a = 5.78, b = 6.57, c = 5.48, Z = 1; alpha = 102.1°, beta = 108.7°, gamma = 90.09° V = 192.74 Den(Calc)= 3.11

Crystal System:

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

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

By Intensity(I/I_o): 3.23(1), 6.4(0.9), 3.03(0.8),

Forms:

Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize
Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu
Help on Above

Forms: [ 1 1 1] [ 1 1 0] [ 0 1 0] [ 0 0 1]

Warning: this large pop-up is very compute intensive and may not work well with some computers.

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Fanfani L , Nunzi A , Zanazzi P F , Acta Crystallographica, Section B , 26 (1970) p.640-645, The crystal structure of fairfieldite, Locality: Foote Mine, North Carolina, USA

Physical Properties of Fairfieldite

Cleavage:

[???] Perfect, [???] Distinct

Color:

Greenish white, White, Light yellow.

Density:

3.1

Diaphaniety:

Transparent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Foliated - Two dimensional platy forms.

Hardness:

3.5 - Copper Penny

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Pearly

Streak:

white

Optical Properties of Fairfieldite

Gladstone-Dale:

CI meas= 0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2081,KPDmeas= 0.2088,KC= 0.2093

Optical Data:

Biaxial (+), a=1.636-1.64, b=1.644-1.65, g=1.654-1.66, bire=0.0180-0.0200, 2V(Calc)=86-88, 2V(Meas)=86. Dispersion relatively weak.

Calculated Properties of Fairfieldite

Electron Density:

r_electron=3.08 gm/cc
note: r_Fairfieldite=3.10 gm/cc.

Fermion Index

Fermion Index = 0.00133
Boson Index = 0.99867

Photoelectric:

PE_Fairfieldite= 7.55 barns/electron
U=PE_Fairfieldite x r_electron= 23.23 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Fairfieldite is Not Radioactive

Fairfieldite Classification

Dana Class:

40.2.2.1 (40)Hydrated Phosphates, etc

(40.2)where A++ (B++)2 (XO4) · x(H2O)

(40.2.2)Fairfieldite Subgroup (Triclinic: P1¯)

40.2.2.1 Fairfieldite Ca2(Mn,Fe)(PO4)2·2(H2O) P1 1

40.2.2.2 Messelite Ca2(Fe,Mn)(PO4)2·2(H2O) P1 1

40.2.2.3 Collinsite Ca2(Mg,Fe)(PO4)2·2(H2O) P1 1

40.2.2.4 Cassidyite Ca2(Ni,Mg)(PO4)2·2(H2O) P1 1

40.2.2.5 Talmessite Ca2Mg(AsO4)2·2(H2O) P1 1

40.2.2.6 Gaitite Ca2Zn(AsO4)2·2(H2O) P1 1

40.2.2.7 Roselite-beta Ca2(Co,Mg)(AsO4)2·2(H2O) P 1 or P1 Tri

40.2.2.8 Parabrandtite Ca2Mn(AsO4)·2(H2O) P1,P 1 Tri

40.2.2.9 Hillite! Ca2(Zn,Mg)[PO4]2·2(H2O) P1 1

Strunz Class:

VII/C.17-30 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.17 - Collinsite - Wendwilsonite series

VII/C.17-10 Collinsite Ca2(Mg,Fe)(PO4)2·2(H2O) P1 1

VII/C.17-15 Hillite! Ca2(Zn,Mg)[PO4]2·2(H2O) P1 1

VII/C.17-20 Messelite Ca2(Fe,Mn)(PO4)2·2(H2O) P1 1

VII/C.17-30 Fairfieldite Ca2(Mn,Fe)(PO4)2·2(H2O) P1 1

VII/C.17-40 Cassidyite Ca2(Ni,Mg)(PO4)2·2(H2O) P1 1

VII/C.17-50 Talmessite Ca2Mg(AsO4)2·2(H2O) P1 1

VII/C.17-60 Gaitite Ca2Zn(AsO4)2·2(H2O) P1 1

VII/C.17-70 Parabrandtite Ca2Mn(AsO4)·2(H2O) P1,P 1 Tri

VII/C.17-80 Roselite-beta Ca2(Co,Mg)(AsO4)2·2(H2O) P 1 or P1 Tri

VII/C.17-90 Wendwilsonite Ca2(Mg,Co)(AsO4)2·2(H2O) P 2₁/c 2/m

VII/C.17-100 Roselite Ca2(Co,Mg)(AsO4)2·2(H2O) P 2₁/c 2/m

VII/C.17-110 Brandtite Ca2(Mn,Mg)(AsO4)2·2(H2O) P 2₁/c 2/m

VII/C.17-120 Zincroselite Ca2Zn(AsO4)2·2(H2O) P 2₁/c 2/m

Other Fairfieldite Information

References:

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

Search for Fairfieldite using:

[ALTAVISTA] [AOL] [About.com] [All-The-Web] [HotBot] [Ixquick] [LookSmart] [MAMMA] [MSN.COM] [Netscape] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Fairfieldite :
AA Mineral Specimens
A-Rocks Auction
Adams Minerals
B and L Minerals
Dakota Matrix
Dan Weinrich Fine Minerals
Dan Weinrich Auctions
e-Rocks Auctions
Excalibur Minerals
Exceptional Minerals
Fabre Minerals
Greenside Minerals
John Betts Fine Minerals
Masons Minerals
Mineral News
Mineral of the Month Club
MineralsWeb Fine Minerals
Minernet.it
Rockshop.cz Kalat Fine Minerals
T G Fine Minerals
Wrights Rock Shop

Translate Fairfieldite Mineral Data :

Ask about Fairfieldite 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 Fairfieldite Specimen Label here :

Fairfieldite

Ca2(Mn,Fe++)(PO4)2·2(H2O)
Dana No: 40.2.2.1 Strunz No: VII/C.17-30
Locality:

Notes: