Ludlamite Mineral Data

General Ludlamite Information

Chemical Formula:

(Fe++,Mg,Mn)3(PO4)2•4(H2O)

Composition:

Molecular Weight = 400.88 gm

Magnesium 5.46 % Mg 9.05 % MgO

Manganese 4.11 % Mn 5.31 % MnO

Iron 25.08 % Fe 32.26 % FeO

Phosphorus 15.45 % P 35.41 % P₂O₅

Hydrogen 2.01 % H 17.98 % H₂O

Oxygen 47.89 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺_1.8Mg_0.9Mn²⁺_0.3(PO₄)₂•4(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1877

Locality:

Wheal Jane, Kea, near Truro, Cornwall, England, UK. Link to MinDat.org Location Data.

Name Origin:

Named for Henry Ludlam (1824-1880), English mineralogist and collector.

Name Pronunciation:

Ludlamite + Pronunciation

Synonym:

ICSD 34254

PDF 35-634

Ludlamite Image

Images:

Ludlamite

Comments: crystal group of Ludlamite.
Location: Huanuni Mine, Oruro Department, Bolivia. Scale: Crystal size 1.5 x 1 cm.
© John Veevaert

Ludlamite Crystallography

Axial Ratios:

a:b:c =2.2688:1:2.0068

Cell Dimensions:

a = 10.541, b = 4.646, c = 9.324, Z = 2; beta = 100.43° V = 449.08 Den(Calc)= 2.96

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): 4.923(1), 4.586(0.85), 3.968(0.5),

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Forms: ( 4 1 2) ( 0 1 1) ( 1 1 1) ( 0 1 2) ( 1 1 0) ( 1 0 0) ( 0 0 1)

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Crystal Structure:

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Abrahams S C , Bernstein J L , Journal of Chemical Physics , 44 (1966) p.2223-2229, Crystal structure of paramagnetic ludlamite, Fe3(PO4)2*4(H2O), at 298 K, Sample: T = 298 K

View Additional jPOWD Structure files for Ludlamite
[1]

Physical Properties of Ludlamite

Cleavage:

{001} Perfect, {100} Indistinct

Color:

Apple green, Colorless, Green, Greenish white, Light green.

Density:

3.15

Diaphaneity:

Transparent to Translucent

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Ludlamite

Gladstone-Dale:

CI meas= 0.004 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.06 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.228,KPDmeas= 0.2143,KC= 0.2151
Ncalc = 1.64 - 1.68

Optical Data:

Biaxial (+), a=1.653, b=1.675, g=1.697, bire=0.0440, 2V(Calc)=88, 2V(Meas)=82. Dispersion r > v.

Calculated Properties of Ludlamite

Electron Density:

Bulk Density (Electron Density)=3.13 gm/cc
note: Specific Gravity of Ludlamite =3.15 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Ludlamite= 9.27 barns/electron
U=PE_Ludlamite x rElectron Density= 29.02 barns/cc.

Radioactivity:

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

Ludlamite Classification

Dana Class:

40.03.05.01 (40)Hydrated Phosphates, etc

(40.03)where (A++)3 (XO4)2 · x(H2O)

(40.03.05)Ludlamite Group

40.03.05.01 Ludlamite (Fe,Mg,Mn)3(PO4)2•4(H2O) P 2₁/a 2/m

40.03.05.02 Metaswitzerite Mn3(PO4)2•4(H2O) P 2/a 2/m

40.03.05.03 Sterlinghillite Mn3(AsO4)2•3(H2O) Mono Mono

40.03.05.04 Switzerite (Mn,Fe)3(PO4)2•7(H2O) P 2₁/a 2/m

Strunz Class:

08.CD.20 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CD -With only medium-sized cations, RO4:H2O = 1:2

08.CD.20 Ludlamite (Fe,Mg,Mn)3(PO4)2•4(H2O) P 2₁/a 2/m

Other Ludlamite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Ludlamite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
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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Ask about Ludlamite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
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Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Ludlamite

(Fe++,Mg,Mn)3(PO4)2•4(H2O)
Dana No: 40.03.05.01 Strunz No: 08.CD.20
Locality:

Notes: