Pahasapaite Mineral Data

General Pahasapaite Information

Chemical Formula:

Li8(Ca,Li,K,Na)11Be24(PO4)24•38(H2O)

Composition:

Molecular Weight = 3,532.65 gm

Potassium 1.33 % K 1.60 % K₂O

Sodium 0.13 % Na 0.18 % Na₂O

Lithium 2.28 % Li 4.91 % Li₂O

Calcium 6.24 % Ca 8.73 % CaO

Beryllium 6.12 % Be 16.99 % BeO

Phosphorus 21.04 % P 48.22 % P₂O₅

Hydrogen 2.17 % H 19.38 % H₂O

Oxygen 60.69 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Li₈Ca_5.5Li_3.6K_1.2Na_0.2Be₂₄(PO₄)₂₄•38(H₂O)

Environment:

late-stage mineral in seams in fractured beryl crystals in a complex granite pegmatite.

IMA Status:

Approved IMA 1987

Locality:

Tip Top mine, 8.5 km southwest of Custer, Custer County, South Dakota, USA. Link to MinDat.org Location Data.

Name Origin:

From Pahasapa, the Lakota Sioux word for Black Hills, South Dakota, USA.

Name Pronunciation:

Pahasapaite + Pronunciation

Synonym:

ICSD 71430

PDF 41-1384

Pahasapaite Image

Images:

Pahasapaite

Comments: Lilac colored pahasapaite in matrix.
Location: Tip Top Mine, Fourmile, Custer District, Custer Co., South Dakota, USA. Scale: Picture size 3.5 mm.
© Thomas Witzke / Abraxas-Verlag

Pahasapaite Crystallography

Cell Dimensions:

a = 13.781, Z = 1; V = 2,617.23 Den(Calc)= 2.24

Crystal System:

Isometric - Tetartoidal H-M Symbol (2 3) Space Group: I 23

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

By Intensity(I/I_o): 9.6(1), 3.248(0.9), 3.684(0.9),

Physical Properties of Pahasapaite

Cleavage:

None

Color:

Colorless, Yellow green, Light pink.

Density:

2.28

Diaphaneity:

Transparent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Pahasapaite

Gladstone-Dale:

CI meas= 0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.007 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2335,KPDmeas= 0.2294,KC= 0.2318
Ncalc = 1.52 - 1.53

Optical Data:

Isotropic, n=1.523.

Calculated Properties of Pahasapaite

Electron Density:

Bulk Density (Electron Density)=2.25 gm/cc
note: Specific Gravity of Pahasapaite =2.24 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_Pahasapaite= 2.02 barns/electron
U=PE_Pahasapaite x r_electron= 4.54 barns/cc.

Radioactivity:

GRapi = 19.22 (Gamma Ray American Petroleum Institute Units)
Concentration of Pahasapaite per GRapi unit = 5.20 (%)

Estimated Radioactivity from Pahasapaite - barely detectable

Pahasapaite Classification

Dana Class:

40.05.07.01 (40)Hydrated Phosphates, etc

(40.05)with miscellaneous formulae

(40.05.07)Dana Group

40.05.07.01 Pahasapaite Li8(Ca,Li,K,Na)11Be24(PO4)24•38(H2O) I 23 2 3

Strunz Class:

08.CA.25 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CA -With small and large/medium cations

08.CA.25 Pahasapaite Li8(Ca,Li,K,Na)11Be24(PO4)24•38(H2O) I 23 2 3

Other Pahasapaite 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 Pahasapaite :
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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Pahasapaite

Li8(Ca,Li,K,Na)11Be24(PO4)24•38(H2O)
Dana No: 40.05.07.01 Strunz No: 08.CA.25
Locality:

Notes:

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