Sphaerobertrandite Mineral Data

General Sphaerobertrandite Information

Chemical Formula:

Be3SiO4(OH)2

Composition:

Molecular Weight = 152.62 gm

Beryllium 17.07 % Be 47.36 % BeO

Silicon 18.59 % Si 39.76 % SiO₂

Hydrogen 1.45 % H 12.93 % H₂O

Oxygen 62.90 % O

______ ______

100.00 % 100.05 % = TOTAL OXIDE

Empirical Formula:

Be_2.89Si_1.01O_3.81(OH)_2.19

Environment:

Found in Be-bearing pegmatites and greisens. Originally named in 1957 and revalidated in 2003.

IMA Status:

Valid Species (Pre-IMA) 1957 (Dana # Added)

Locality:

Mannepakhk Mountain,Lovozero massif, Russia. Link to MinDat.org Location Data.

Name Origin:

The name alludes to the typical spherulitic morphology and the similarity to bertrandite in the main chemical constituents.

Name Pronunciation:

Sphaerobertrandite + Pronunciation

Sphaerobertrandite Image

Images:

Sphaerobertrandite

Comments: White to pale brownish, radial-concentric aggregates of sphaerobertrandite.
Location: Sengischorr Mt, Lovozero Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Sphaerobertrandite Crystallography

Axial Ratios:

a:b:c =1.0952:1:3.8077

Cell Dimensions:

a = 5.081, b = 4.639, c = 17.664, Z = 4; beta = 106.09° V = 400.04 Den(Calc)= 2.53

Crystal System:

Monoclinic - Sphenoidal H-M Symbol (2) Space Group: P 2

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

By Intensity(I/I_o): 3.161(1)(111,113), 2.318(0.9)(020), 4.885(0.9)(100),2.836(0.7)(104), 4.236(0.62)(004),

Physical Properties of Sphaerobertrandite

Cleavage:

{001} Perfect, {010} Distinct

Color:

Colorless, Yellow, Brownish white, White, Gray.

Density:

2.46 - 2.54, Average = 2.5

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Platy - Sheet forms (e.g. micas).

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Sphaerobertrandite

Gladstone-Dale:

CI meas= -0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.002 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2398,KPDmeas= 0.2427,KC= 0.2403
Ncalc = 1.59 - 1.61

Optical Data:

Biaxial (-), a=1.597, b=1.607, g=1.616, bire=0.0190, 2V(Calc)=86, 2V(Meas)=86.5. Dispersion none.

Calculated Properties of Sphaerobertrandite

Electron Density:

Bulk Density (Electron Density)=2.52 gm/cc
note: Specific Gravity of Sphaerobertrandite =2.53 gm/cc.

Fermion Index:

Fermion Index = 0.17
Boson Index = 0.83

Photoelectric:

PE_{Sphaerobertrandite}= 0.91 barns/electron
U=PE_{Sphaerobertrandite} x rElectron Density= 2.29 barns/cc.

Radioactivity:

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

Sphaerobertrandite Classification

Dana Class:

52.01.02.01 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.01)with cations in [4] coordination

(52.01.02)Dana Group

52.01.02.01 Sphaerobertrandite! Be3SiO4(OH)2 P 2 2

Strunz Class:

09.AE.50 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AE -Nesosilicates with additional (O,OH,F,H2O);

09.AE.50 Sphaerobertrandite Be3SiO4(OH)2 P 2 2

Other Sphaerobertrandite Information

References:

NAME( AmMin, v 88, p 1839) PHYS. PROP.(AmMin, v 88, p 1839) OPTIC PROP.(AmMin, v 88, p 1839)

See Also:

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

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

Sphaerobertrandite

Be3SiO4(OH)2
Dana No: 52.01.02.01 Strunz No: 09.AE.50
Locality:

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