Cahnite Mineral Data

General Cahnite Information

Chemical Formula:

Ca2B(AsO4)(OH)4

Composition:

Molecular Weight = 297.91 gm

Calcium 26.91 % Ca 37.65 % CaO

Boron 3.63 % B 11.68 % B₂O₃

Arsenic 25.15 % As 38.57 % As₂O₅

Hydrogen 1.35 % H 12.09 % H₂O

Oxygen 42.96 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂B(AsO₄)(OH)₄

Environment:

A late-stage mineral in pegmatites cutting a metamorphosed stratiform zinc orebody.

IMA Status:

Valid Species (Pre-IMA) 1927

Locality:

From Franklin, Sussex Co., New Jersey, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Lazard Cahn (1865-1940), mineral collector and dealer, Colorado Springs, Colorado, USA, who first noted the species.

Name Pronunciation:

Cahnite

Synonym:

ICSD 27527

PDF 13-158

Cahnite Image

Images:

Cahnite

Comments: White, translucent cahnite crystal on hodgkinsonite.
Location: Franklin, Sussex County, New Jersey, USA. Scale: Size Not Given.
© Lou Perloff / Photo Atlas of Minerals

Cahnite Crystallography

Axial Ratios:

a:c = 1:0.87244

Cell Dimensions:

a = 7.095, c = 6.19, Z = 2; V = 311.60 Den(Calc)= 3.18

Crystal System:

Tetragonal - DisphenoidalH-M Symbol (4) Space Group: I 4

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

By Intensity(I/I_o): 3.56(1), 1.818(0.55), 2.64(0.5),

Forms:

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Forms: ( 0 1 0) ( 1 1 0) ( 1 1 1)

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Crystal Structure:

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Prewitt C T , Buerger M J , American Mineralogist , 46 (1961) p.1077-1085, The crystal structure of cahnite, Ca2BAsO4(OH)4

Physical Properties of Cahnite

Cleavage:

{???} Perfect

Color:

Colorless, White.

Density:

3.16

Diaphaneity:

Transparent

Fracture:

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

Hardness:

3 - Calcite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Cahnite

Gladstone-Dale:

CI meas= -0.009 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2083,KPDmeas= 0.2097,KC= 0.2078
Ncalc = 1.66

Optical Data:

Uniaxial (+), w=1.662, e=1.663, bire=0.0010.

Calculated Properties of Cahnite

Electron Density:

Bulk Density (Electron Density)=3.12 gm/cc
note: Specific Gravity of Cahnite =3.18 gm/cc.

Fermion Index:

Fermion Index = 0.0077923115
Boson Index = 0.9922076885

Photoelectric:

PE_Cahnite= 20.05 barns/electron
U=PE_Cahnite x rElectron Density= 62.50 barns/cc.

Radioactivity:

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

Cahnite Classification

Dana Class:

43.04.04.01 (43)Compound Phosphates, etc.

(43.04)(Anhydrous Compound Anions With Hydroxyl or Halogen)

(43.04.04)Dana Group

43.04.04.01 Cahnite Ca2B(AsO4)(OH)4 I 4 4

Strunz Class:

06.AC.70 06 - BORATES

06.A - Monoborates

06.AC -B(O,OH)4, without and with additional anions; 1(T), 1(T)+OH, etc.

06.AC.70 Cahnite Ca2B(AsO4)(OH)4 I 4 4

Other Cahnite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

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

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

Cahnite

Ca2B(AsO4)(OH)4
Dana No: 43.04.04.01 Strunz No: 06.AC.70
Locality:

Notes: