Tancoite Mineral Data

General Tancoite Information

Chemical Formula:

HNa2LiAl(PO4)2(OH)

Composition:

Molecular Weight = 287.86 gm

Sodium 15.97 % Na 21.53 % Na₂O

Lithium 2.41 % Li 5.19 % Li₂O

Aluminum 9.37 % Al 17.71 % Al₂O₃

Phosphorus 21.52 % P 49.31 % P₂O₅

Hydrogen 0.70 % H 6.26 % H₂O

Oxygen 50.02 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

LiNa₂HAl(PO₄)₂(OH)

IMA Status:

Approved IMA 1979

Locality:

Tanco spodumene-bearing pegmatite mine at Bernic Lake, MB, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Tancoite

Synonym:

ICSD 31274

IMA1979-045

PDF 33-602

Tancoite Image

Images:

Tancoite

Comments: SEM image of tabular tancoite crystals.
Location: Tanco Mine, Manitoba, Canada. Scale: Field of View 1 mm.
© Royal Ontario Museum

Tancoite Crystallography

Axial Ratios:

a:b:c =0.4983:1:0.4936

Cell Dimensions:

a = 7.041, b = 14.13, c = 6.975, Z = 4; V = 693.94 Den(Calc)= 2.76

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pbcb

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

By Intensity(I/I_o): 3.15(1), 4.672(1), 3.413(0.9),

Physical Properties of Tancoite

Cleavage:

{010} Distinct, {001} Distinct

Color:

Colorless, Light pink.

Density:

2.752

Diaphaneity:

Transparent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Columnar - Forms columns

Habit:

Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces.

Hardness:

4-4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Tancoite

Gladstone-Dale:

CI meas= 0.015 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2014,KPDmeas= 0.202,KC= 0.205
Ncalc = 1.56 - 1.57

Optical Data:

Biaxial (-), a=1.541, b=1.563, g=1.564, bire=0.0230, 2V(Calc)=22, 2V(Meas)=23. Dispersion weak, r < v.

Calculated Properties of Tancoite

Electron Density:

Bulk Density (Electron Density)=2.72 gm/cc
note: Specific Gravity of Tancoite =2.75 gm/cc.

Fermion Index:

Fermion Index = 0.0020495888
Boson Index = 0.9979504112

Photoelectric:

PE_Tancoite= 1.58 barns/electron
U=PE_Tancoite x rElectron Density= 4.30 barns/cc.

Radioactivity:

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

Tancoite Classification

Dana Class:

41.04.07.01 (41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen

(41.04)where (A B)5 (XO4)2 Zq

(41.04.07)Dana Group

41.04.07.01 Tancoite HNa2LiAl(PO4)2(OH) Pbcb 2/m 2/m 2/m

Strunz Class:

08.BG.15 08 - PHOSPHATES, ARSENATES, VANADATES

08.B - Phosphates, etc. with Additional Anions, without H2O

08.BG -With medium-sized and large cations, (OH, etc.):RO4 = 0.5:1

08.BG.15 Tancoite HNa2LiAl(PO4)2(OH) Pbcb 2/m 2/m 2/m

Other Tancoite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Tancoite :
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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Print or Cut-and-Paste your Tancoite Specimen Label here :

Tancoite

HNa2LiAl(PO4)2(OH)
Dana No: 41.04.07.01 Strunz No: 08.BG.15
Locality:

Notes:

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