Margarite Mineral Data

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."

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

Diaphaniety:

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:

None.

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

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:

r_electron=3.02 gm/cc
note: r_Margarite=3.04 gm/cc.

Fermion Index

Fermion Index = 0.00695
Boson Index = 0.99305

Photoelectric:

PE_Margarite= 2.58 barns/electron
U=PE_Margarite x r_electron= 7.79 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Margarite is Not Radioactive

Margarite Classification

Dana Class:

71.2.2c.1 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.2)with 2:1 Layers

(71.2.2c)Mica Group (Margarite subgroup)

71.2.2c.1 Margarite CaAl2(Al2Si2)O10(OH)2 C 2/c 2/m

71.2.2c.2 Clintonite Ca(Mg,Al)3(Al3Si)O10(OH)2 C 2/m 2/m

71.2.2c.3 Bityite CaLiAl2(AlBeSi2)O10(OH)2 C 2/c 2/m

71.2.2c.4 Anandite (Ba,K)(Fe,Mg)3(Si,Al,Fe)4O10(S,OH)2 C 2/m 2/m

71.2.2c.5 Kinoshitalite (Ba,K)(Mg,Mn,Al)3Si2Al2O10(OH)2 C 2/m 2/m

71.2.2c.6 Ferrokinoshitalite! (Ba,K)(Fe,Mg)3(Si2Al2)O10(OH,F)2 C 2/m 2/m

71.2.2c.7 Ganterite! [Ba0.5(Na,K)0.5]Al2(Si2.5Al1.5O10)(OH)2 C 2/c 2/m

71.2.2c.8 IMA2004-013! (Ba,K)(Mg,Fe,Ti)3(Si,Al)4O10O2 C 2/m 2/m

Strunz Class:

VIII/H.12-40 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like layered silicates with [Si4O10]4- and related groups

VIII/H.12 - Mica group, Lepidolite series

VIII/H.12-10 Anandite (Ba,K)(Fe,Mg)3(Si,Al,Fe)4O10(S,OH)2 C 2/m 2/m

VIII/H.12-20 Bityite CaLiAl2(AlBeSi2)O10(OH)2 C 2/c 2/m

VIII/H.12-30 Kinoshitalite (Ba,K)(Mg,Mn,Al)3Si2Al2O10(OH)2 C 2/m 2/m

VIII/H.12-35 Ferrokinoshitalite! (Ba,K)(Fe,Mg)3(Si2Al2)O10(OH,F)2 C 2/m 2/m

VIII/H.12-40 Margarite CaAl2(Al2Si2)O10(OH)2 C 2/c 2/m

VIII/H.12-50 Chernykhite (Ba,Na)V,Al)2(Si,Al)4O10(OH)2 C 2/c 2/m

VIII/H.12-60 Clintonite Ca(Mg,Al)3(Al3Si)O10(OH)2 C 2/m 2/m

Other Margarite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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Margarite

CaAl2(Al2Si2)O10(OH)2
Dana No: 71.2.2c.1 Strunz No: VIII/H.12-40
Locality:

Notes: