Pezzottaite Mineral Data

General Pezzottaite Information

Chemical Formula:

Cs(Be2Li)Al2Si6O18

Composition:

Molecular Weight = 658.80 gm

Cesium 14.93 % Cs 15.83 % Cs₂O

Potassium 0.06 % K 0.07 % K₂O

Rubidium 0.52 % Rb 0.57 % Rb₂O

Sodium 1.40 % Na 1.88 % Na₂O

Lithium 0.99 % Li 2.13 % Li₂O

Beryllium 4.19 % Be 11.62 % BeO

Aluminum 8.35 % Al 15.79 % Al₂O₃

Silicon 25.58 % Si 54.72 % SiO₂

Hydrogen 0.03 % H 0.27 % H₂O

Oxygen 43.96 % O

______ ______

100.00 % 102.88 % = TOTAL OXIDE

Empirical Formula:

Cs_0.74Rb_0.04K_0.01Na_0.4Be_3.06Li_0.94Al_2.04Si₆O₁₈(H₂O)_0.1

Environment:

Late-stage pocket mineral formed in a granitic pegmatite. Beryl group

IMA Status:

Approved IMA 2004 (Dana # Added)

Locality:

Sakavalana pegmatite, located 25 km south of the village of Mandosonoro, SW of Antsirabe, Fianarantsoa province, central Madagascar. Link to MinDat.org Location Data.

Name Origin:

Named for Federico Pezzotta of the Museo Civico, Milano, Italy for his work on the granitic pegmatites of Madagascar.

Synonym:

IMA2003-022

Pezzottaite Image

Images:

Pezzottaite

Comments: Hot-pink, hexagonal, floater crystal of pezzottaite.
Location: Ambatovita, Mandrosonoro, Antsirabe, Madagascar. Scale: Crystal size 1.6x1.2x0.6 cm.
© Fabre Minerals

Pezzottaite Crystallography

Axial Ratios:

a:c = 1:1.74357

Cell Dimensions:

a = 15.946, c = 27.803, Z = 18; V = 6,122.46 Den(Calc)= 3.22

Crystal System:

Trigonal - Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3c

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

By Intensity(I/I_o): 3.271(1)(036), 2.871(0.52)(153), 3.027(0.41)(146), 3.09(0.29)(150), 3.019(0.29), 1.636(0.14)(0.6.12), 2.215(0.14)(207), 1.749(0.12)(3

Physical Properties of Pezzottaite

Cleavage:

{001} Imperfect

Color:

Raspberry red, Pink.

Density:

2.97

Diaphaneity:

Translucent to transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Hexagonal - Six-sided crystal shape in cross-section or habit.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

8 - Topaz

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Pezzottaite

Gladstone-Dale:

CI meas= -0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.075 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1898,KPDmeas= 0.2057,KC= 0.2051
Ncalc = 1.61 - 1.66

Optical Data:

Uniaxial (-), e=1.601-1.611, w=1.612-1.62, bire=0.0090-0.0110.

Calculated Properties of Pezzottaite

Electron Density:

Bulk Density (Electron Density)=2.86 gm/cc
note: Specific Gravity of Pezzottaite =2.97 gm/cc.

Fermion Index:

Fermion Index = 0.05
Boson Index = 0.95

Photoelectric:

PE_Pezzottaite= 60.91 barns/electron
U=PE_Pezzottaite x r_electron= 174.27 barns/cc.

Radioactivity:

GRapi = 212.96 (Gamma Ray American Petroleum Institute Units)
Concentration of Pezzottaite per GRapi unit = 0.47 (%)

Estimated Radioactivity from Pezzottaite - barely detectable

Pezzottaite Classification

Dana Class:

61.01.01.05 (61)Cyclosilicate Six-Membered Rings

(61.01)with [Si6O18] rings; possible (OH) and Al substitution

(61.01.01)Beryl group

61.01.01.01 Beryl Be3Al2Si6O18 P 6/mmc 6/m 2/m 2/m

61.01.01.02 Bazzite Be3(Sc,Al)2Si6O18 P 6/mcc 6/m 2/m 2/m

61.01.01.03 Indialite Mg2Al4Si5O18 P 6/mcc 6/m 2/m 2/m

61.01.01.04 Stoppaniite! (Fe,Al,Mg)4(Na,[])2[Be6Si12O36]•2(H2O) P 6/mmc 6/m 2/m 2/m

61.01.01.05 Pezzottaite! Cs(Be2Li)Al2Si6O18 R 3c 3m

Strunz Class:

09.CJ.05 09 - SILICATES (Germanates)

09.C - Cyclosilicates

09.CJ -[Si6O18]12- 6-membered single rings (sechser-Einfachringe),

09.CJ.05 Beryl Be3Al2Si6O18 P 6/mmc 6/m 2/m 2/m

09.CJ.05 Bazzite Be3(Sc,Al)2Si6O18 P 6/mcc 6/m 2/m 2/m

09.CJ.05 Indialite Mg2Al4Si5O18 P 6/mcc 6/m 2/m 2/m

09.CJ.05 Stoppaniite! (Fe,Al,Mg)4(Na,[])2[Be6Si12O36]•2(H2O) P 6/mmc 6/m 2/m 2/m

09.CJ.05 Pezzottaite! Cs(Be2Li)Al2Si6O18 R 3c 3m

Other Pezzottaite Information

References:

NAME( MinRec 35:369) PHYS. PROP.(MinRec 35:369) OPTIC PROP.(MinRec 35:369)

See Also:

Links to other databases for Pezzottaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineral and Gemstone Kingdom
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info

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Pezzottaite

Cs(Be2Li)Al2Si6O18
Dana No: 61.01.01.05 Strunz No: 09.CJ.05
Locality:

Notes:

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