Nacrite Mineral Data

General Nacrite Information

Chemical Formula:

Al2Si2O5(OH)4

Composition:

Molecular Weight = 258.16 gm

Aluminum 20.90 % Al 39.50 % Al₂O₃

Silicon 21.76 % Si 46.55 % SiO₂

Hydrogen 1.56 % H 13.96 % H₂O

Oxygen 55.78 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Al₂Si₂O₅(OH)₄

Environment:

May be the same as kaolinite or dickite. Hydrothermal origin.

IMA Status:

Valid Species (Pre-IMA) 1807

Locality:

Link to MinDat.org Location Data.

Name Origin:

From the French, nacre, "mother-of-pearl."

Name Pronunciation:

Nacrite

Nacrite Image

Images:

Nacrite

Comments: Colorless, transparent crystal of macrite on matrix.
Location: Hunersedge mine, Baden-Wurttemburg, Germany. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Nacrite Crystallography

Axial Ratios:

a:b:c =1.7312:1:3.0503

Cell Dimensions:

a = 8.909, b = 5.146, c = 15.697, Z = 4; beta = 113.7° V = 658.95 Den(Calc)= 2.60

Crystal System:

Monoclinic - DomaticH-M Symbol (m) Space Group: Cc

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

By Intensity(I/I_o): 7.187(1), 3.593(0.53), 4.383(0.39),

Crystal Structure:

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Zheng H , Bailey S W , Clays and Clay Minerals , 42 (1994) p.46-52, Refinement of the nacrite structure, Locality: Red Mountain near Silverton, Colorado, USA

Physical Properties of Nacrite

Cleavage:

{001} Perfect

Color:

Colorless, White, Yellowish, Brownish.

Density:

2.6

Diaphaneity:

Transparent

Fracture:

Earthy - Dull, clay-like fractures with no visible crystalline affinities, (e.g. howlite).

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Scaly - Morphology like fish scales.

Hardness:

1 - Talc

Luster:

Pearly

Streak:

white

Optical Properties of Nacrite

Gladstone-Dale:

CI meas= 0.046 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.046 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2156,KPDmeas= 0.2156,KC= 0.226
Ncalc = 1.59

Optical Data:

Biaxial (-), a=1.557, b=1.562, g=1.563, bire=0.0060, 2V(Calc)=48, 2V(Meas)=40.

Calculated Properties of Nacrite

Electron Density:

Bulk Density (Electron Density)=2.62 gm/cc
note: Specific Gravity of Nacrite =2.60 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Nacrite= 1.48 barns/electron
U=PE_Nacrite x rElectron Density= 3.87 barns/cc.

Radioactivity:

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

Nacrite Classification

Dana Class:

71.01.01.03 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.01)with 1:1 layers

(71.01.01)Kaolinite group

71.01.01.01 Dickite Al2Si2O5(OH)4 Cc m

71.01.01.02 Kaolinite Al2Si2O5(OH)4 P1 1

71.01.01.03 Nacrite Al2Si2O5(OH)4 Cc m

71.01.01.04 Halloysite Al2Si2O5(OH)4 Cc m

71.01.01.04a Endellite? Al2Si2O5(OH)4•2(H2O) Cc m

71.01.01.05 Odinite (Fe,Mg,Al,Fe,Ti,Mn)2.5(Si,Al)2O5(OH)4 Cm m

Strunz Class:

09.ED.05 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.ED -Phyllosilicates with kaolinite layers

09.ED.05 Dickite Al2Si2O5(OH)4 Cc m

09.ED.05 Kaolinite Al2Si2O5(OH)4 P1 1

09.ED.05 Nacrite Al2Si2O5(OH)4 Cc m

Other Nacrite Information

References:

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

See Also:

Links to other databases for Nacrite :
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
15 - WWW-MINCRYST

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Ask about Nacrite here :
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Print or Cut-and-Paste your Nacrite Specimen Label here :

Nacrite

Al2Si2O5(OH)4
Dana No: 71.01.01.03 Strunz No: 09.ED.05
Locality:

Notes: