Margarite Mineral Data

General Margarite Information

Chemical Formula:

CaAl2(Al2Si2)O10(OH)2

Composition:

Molecular Weight = 398.18 gm

Calcium 10.07 % Ca 14.08 % CaO

Aluminum 27.10 % Al 51.21 % Al₂O₃

Silicon 14.11 % Si 30.18 % SiO₂

Hydrogen 0.51 % H 4.52 % H₂O

Oxygen 48.22 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaAl₄Si₂O₁₀(OH)₂

Environment:

Commonly associated with corundum as an alteration product.

IMA Status:

Valid Species (Pre-IMA) 1823

Locality:

Corundum mines at Ekaterinurg Distict, Ural Mountains, Russia. Link to MinDat.org Location Data.

Name Origin:

From the Greek margaritos - "pearl."

Name Pronunciation:

Margarite

Margarite Image

Images:

Margarite

Comments: Beige, massive, fibrous/foliated aggregate of margarite crystals.
Location: Long Hill/Old Tungsten Mine in Trumbull, Connecticut, USA. Scale: 10 x 5 cm.
© Walter Mroch / Gem and Mineral Exploration Company

Margarite Crystallography

Axial Ratios:

a:b:c =0.5816:1:2.1774

Cell Dimensions:

a = 5.118, b = 8.799, c = 19.159, Z = 4; beta = 95.15° V = 859.31 Den(Calc)= 3.08

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c

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

By Intensity(I/I_o): 3.18(1), 1.908(0.35), 2.517(0.25),

Crystal Structure:

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Guggenheim S , Bailey S W , American Mineralogist , 63 (1978) p.186-187, Refinement of the margarite structure in subgroup symmetry: correction,, further refinement, and comments

Physical Properties of Margarite

Cleavage:

{001} Good

Color:

White, Gray, Pinkish gray, Yellowish gray.

Density:

2.99 - 3.08, Average = 3.03

Diaphaneity:

Translucent to subtranslucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Lamellar - Thin laminae producing a lamellar structure.

Habit:

Massive - Lamellar - Distinctly foliated fine-grained forms.

Habit:

Scaly - Morphology like fish scales.

Hardness:

4 - Fluorite

Luminescence:

Fluorescent, Short UV=sky blue, Long UV=strong sky blue.

Luster:

Pearly

Streak:

white

Optical Properties of Margarite

Gladstone-Dale:

CI meas= 0.028 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.042 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2047,KPDmeas= 0.2077,KC= 0.2137
Ncalc = 1.64 - 1.66

Optical Data:

Biaxial (-), a=1.595-1.638, b=1.625-1.648, g=1.627-1.65, bire=0.0120-0.0320, 2V(Calc)=28-46, 2V(Meas)=26-67. Dispersion r < v.

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Margarite

Electron Density:

Bulk Density (Electron Density)=3.02 gm/cc
note: Specific Gravity of Margarite =3.04 gm/cc.

Fermion Index:

Fermion Index = 0.0069559576
Boson Index = 0.9930440424

Photoelectric:

PE_Margarite= 2.58 barns/electron
U=PE_Margarite x rElectron Density= 7.79 barns/cc.

Radioactivity:

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

Margarite Classification

Dana Class:

71.02.02c.01 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.02)with 2:1 Layers

(71.02.02c)Mica Group (Margarite subgroup)

71.02.02c.01 Margarite CaAl2(Al2Si2)O10(OH)2 C 2/c 2/m

71.02.02c.02 Clintonite Ca(Mg,Al)3(Al3Si)O10(OH)2 C 2/m 2/m

71.02.02c.03 Bityite CaLiAl2(AlBeSi2)O10(OH)2 C 2/c 2/m

71.02.02c.04 Anandite (Ba,K)(Fe,Mg)3(Si,Al,Fe)4O10(S,OH)2 C 2/m 2/m

71.02.02c.05 Kinoshitalite (Ba,K)(Mg,Mn,Al)3Si2Al2O10(OH)2 C 2/m 2/m

71.02.02c.06 Ferrokinoshitalite! (Ba,K)(Fe,Mg)3(Si2Al2)O10(OH,F)2 C 2/m 2/m

71.02.02c.07 Ganterite! [Ba0.5(Na,K)0.5]Al2(Si2.5Al1.5O10)(OH)2 C 2/c 2/m

71.02.02c.08 Oxykinoshitalite! (Ba,K)(Mg,Fe,Ti)3(Si,Al)4O10O2 C 2/m 2/m

Strunz Class:

09.EC.30 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.30 Margarite CaAl2(Al2Si2)O10(OH)2 C 2/c 2/m

Other Margarite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Collectors Book of Fluorescent Minerals) OPTIC PROP.(Heinrich65)

See Also:

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

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Ask about Margarite 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 Margarite Specimen Label here :

Margarite

CaAl2(Al2Si2)O10(OH)2
Dana No: 71.02.02c.01 Strunz No: 09.EC.30
Locality:

Notes: