Bertrandite Mineral Data (original) (raw)
General Bertrandite Information
Chemical Formula:
Be4Si2O7(OH)2
Composition:
Molecular Weight = 238.23 gm
Beryllium 15.13 % Be 42.00 % BeO
Silicon 23.58 % Si 50.44 % SiO2
Hydrogen 0.85 % H 7.56 % H2O
Oxygen 60.44 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Be4(Si2O7)(OH)2
Environment:
Commonly found in Be-bearing pegmatites and may be derived from the alteration of beryl.
IMA Status:
Valid Species (Pre-IMA) 1883
Locality:
Discovered at near Nantes, Loire-Inferieure, France. Also found at Irkutka and Altai Mountains, Siberia, Russia. Link to MinDat.org Location Data.
Name Origin:
Named after the French mineralogist, E. Bertrand.
Name Pronunciation:
Bertrandite + Pronunciation 
Synonym:
ICSD 202360
PDF 24-509
Bertrandite Image
Images:
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Bertrandite Comments: Colorless prismatic crystals of bertrandite on matrix with pale pink rhombohedral crystals of rhodochrosite. Location: Yiaoguanshen mine, Hunan Province, China.Scale: 3.5 x 4 cm. © Dan Weinrich |
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Images:
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Bertrandite Comments: Fan-like clusters of bertrandite crystals with brown rhodochrosite and quartz. Location: Kara Oba, Kazakhstan.Scale: Crystal size 1.1 cm. © John Veevaert |
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Bertrandite Crystallography
Axial Ratios:
a:b:c =1.7514:1:0.5224
Cell Dimensions:
a = 15.22, b = 8.69, c = 4.54, Z = 4; V = 600.47 Den(Calc)= 2.64
Crystal System:
Orthorhombic - PyramidalH-M Symbol (mm2) Space Group: Ccm21
X Ray Diffraction:
By Intensity(I/Io): 4.38(1), 3.19(0.9), 2.54(0.8),
Crystal Structure:
Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above
| | Downs J W , Ross F K , American Mineralogist , 72 (1987) p.979-983, Neutron-diffraction study of bertrandite, Note: O2y has been corrected View Additional jPOWD Structure files for Bertrandite [1] [2] [3] | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
Physical Properties of Bertrandite
Cleavage:
{001} Perfect, {110} Distinct, {101} Distinct
Color:
Colorless, Pale yellow.
Density:
2.59 - 2.6, Average = 2.59
Diaphaneity:
Translucent to transparent
Fracture:
Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Crystalline - Fine - Occurs as well-formed fine sized crystals.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Habit:
Tabular - Form dimensions are thin in one direction.
Hardness:
6-7 - Orthoclase-Quartz
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Magnetism:
Nonmagnetic
Streak:
white
Optical Properties of Bertrandite
Gladstone-Dale:
CI meas= -0.005 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2285,KPDmeas= 0.2325,KC= 0.2314
Ncalc = 1.6 - 1.61
Optical Data:
Biaxial (-), a=1.591, b=1.605, g=1.614, bire=0.0230, 2V(Calc)=76, 2V(Meas)=73-81. Dispersion none.
Pleochroism (x):
none.
Pleochroism (y):
none.
Pleochroism (z):
none.
Calculated Properties of Bertrandite
Electron Density:
Bulk Density (Electron Density)=2.57 gm/cc
note: Specific Gravity of Bertrandite =2.60 gm/cc.
Fermion Index:
Fermion Index = 0.16
Boson Index = 0.84
Photoelectric:
PEBertrandite = 1.07 barns/electron
U=PEBertrandite x rElectron Density= 2.75 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Bertrandite is Not Radioactive
Bertrandite Classification
Dana Class:
56.01.01.01 (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O
(56.01)with cations in [4] coordination
(56.01.01)Dana Group
56.01.01.01 Bertrandite Be4Si2O7(OH)2 Ccm21 mm2
Strunz Class:
09.BD.05 09 - SILICATES (Germanates)
09.B - Sorosilicates
09.BD -Si2O7 groups with additional anions;
09.BD.05 Bertrandite Be4Si2O7(OH)2 Ccm21 mm2
Other Bertrandite Information
References:
NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)
See Also:
Links to other databases for Bertrandite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - Scandinavian mineral gallery
17 - WWW-MINCRYST
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Print or Cut-and-Paste your Bertrandite Specimen Label here :
Bertrandite
Be4Si2O7(OH)2
Dana No: 56.01.01.01 Strunz No: 09.BD.05
Locality:
Notes: