Mineralogy Database

Bertrandite Mineral Data

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General Bertrandite Information

Help on Chemical  Formula: Chemical Formula: Be4Si2O7(OH)2
Help on Composition: 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
Help on Empirical Formula: Empirical Formula: Be4(Si2O7)(OH)2
Help on Environment: Environment: Commonly found in Be-bearing pegmatites and may be derived from the alteration of beryl.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1883
Help on Locality: Locality: Discovered at near Nantes, Loire-Inferieure, France. Also found at Irkutka and Altai Mountains, Siberia, Russia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the French mineralogist, E. Bertrand.
Help on Name Pronunciation: Name Pronunciation: Bertrandite + Pronunciation Say BERTRANDITE
Help on Synonym: Synonym: ICSD 202360
  PDF 24-509

Bertrandite Image

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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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Comments: Fan-like clusters of bertrandite crystals with brown rhodochrosite and quartz.
Location: Kara Oba, Kazakhstan. Scale: Crystal size 1.1 cm.
© John Veevaert

Bertrandite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.7514:1:0.5224
Help on Cell Dimensions: Cell Dimensions: a = 15.22, b = 8.69, c = 4.54, Z = 4; V = 600.47 Den(Calc)= 2.64
Help on Crystal System: Crystal System: Orthorhombic - Pyramidal H-M Symbol (mm2) Space Group: Ccm21
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 4.38(1), 3.19(0.9), 2.54(0.8),

Physical Properties of Bertrandite

Help on Cleavage: Cleavage: {001} Perfect, {110} Distinct, {101} Distinct
Help on Color: Color: Colorless, Pale yellow.
Help on Density: Density: 2.59 - 2.6, Average = 2.59
Help on Diaphaneity: Diaphaneity: Translucent to transparent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Crystalline - Fine - Occurs as well-formed fine sized crystals.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Habit: Habit: Tabular - Form dimensions are thin in one direction.
Help on Hardness: Hardness: 6-7 - Orthoclase-Quartz
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous (Glassy)
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: white

Optical Properties of Bertrandite

Help on Gladstone-Dale: 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
Help on Optical Data: Optical Data: Biaxial (-), a=1.591, b=1.605, g=1.614, bire=0.0230, 2V(Calc)=76, 2V(Meas)=73-81. Dispersion none.
Help on Pleochroism (x): Pleochroism (x): none.
Help on Pleochroism (y): Pleochroism (y): none.
Help on Pleochroism (z): Pleochroism (z): none.

Calculated Properties of Bertrandite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.57 gm/cc
note: Specific Gravity of Bertrandite =2.60 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.16
Boson Index = 0.84
Help on Photoelectric: Photoelectric: PEBertrandite = 1.07 barns/electron
U=PEBertrandite x rElectron Density= 2.75 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Bertrandite is Not Radioactive

Bertrandite Classification

Help on  Dana Class: Dana Class: (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O
  (56.01)with cations in [4] coordination
  (56.01.01)Dana Group Bertrandite Be4Si2O7(OH)2 Ccm21 mm2
Help on  Strunz Class: 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

Help on References: References: NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)
Help on See Also: 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

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Dana No: Strunz No: 09.BD.05





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