Pentahydroborite Mineral Data

General Pentahydroborite Information

Chemical Formula:

CaB2O(OH)6•2(H2O)

Composition:

Molecular Weight = 215.77 gm

Calcium 18.57 % Ca 25.99 % CaO

Boron 10.02 % B 32.26 % B₂O₃

Hydrogen 4.67 % H 41.75 % H₂O

Oxygen 66.73 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaB₂O(OH)₆•2(H₂O)

Environment:

Skarn mineral.

IMA Status:

Approved IMA 1962

Locality:

Solongo, Transbaikalia, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for the composition.

Name Pronunciation:

Pentahydroborite + Pronunciation

Synonym:

ICSD 200083

PDF 14-339

Pentahydroborite Image

Images:

Pentahydroborite

Comments: Transparent, tabular crystal of pentahydroborite on massive material.
Location: Fuka Mine, Bicchu Town, Kawakama Co., Okayama Pref., Japan. Scale: Crystal size 0.8 cm.
© John Veevaert

Pentahydroborite Crystallography

Axial Ratios:

a:b:c =1.2022:1:1.245

Cell Dimensions:

a = 7.845, b = 6.525, c = 8.124, Z = 2; alpha = 111.62°, beta = 111.9°, gamma = 73.44° V = 343.82 Den(Calc)= 2.08

Crystal System:

Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 7.04(1), 2.99(0.9), 3.54(0.8),

Physical Properties of Pentahydroborite

Cleavage:

None

Color:

Colorless.

Density:

2 - 2.03, Average = 2.01

Diaphaneity:

Transparent

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

2.5 - Finger Nail

Luminescence:

Fluorescent, Short UV=violet.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Pentahydroborite

Gladstone-Dale:

CI meas= -0.002 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.005 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2645,KPDmeas= 0.2665,KC= 0.2659
Ncalc = 1.53 - 1.54

Optical Data:

Biaxial (+), a=1.531, b=1.536, g=1.544, bire=0.0130

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Pentahydroborite

Electron Density:

Bulk Density (Electron Density)=2.09 gm/cc
note: Specific Gravity of Pentahydroborite =2.02 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_{Pentahydroborite}= 2.45 barns/electron
U=PE_{Pentahydroborite} x rElectron Density= 5.12 barns/cc.

Radioactivity:

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

Pentahydroborite Classification

Dana Class:

26.02.01.01 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.02)Dana Type

(26.02.01)Dana Group

26.02.01.01 Pentahydroborite CaB2O(OH)6•2(H2O) P1 1

Strunz Class:

06.BB.10 06 - BORATES

06.B - Diborates

06.BB -Neso-diborates with double tetrahedra B2O(OH)6; 2(2T)

06.BB.10 Pentahydroborite CaB2O(OH)6•2(H2O) P1 1

Other Pentahydroborite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8;Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Pentahydroborite :
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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Pentahydroborite

CaB2O(OH)6•2(H2O)
Dana No: 26.02.01.01 Strunz No: 06.BB.10
Locality:

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