Hydroboracite Mineral Data

Hydroboracite Mineral Data +

General Hydroboracite Information

Chemical Formula:

CaMgB6O8(OH)6·3(H2O)

Composition:

Molecular Weight = 413.33 gm

Calcium 9.70 % Ca 13.57 % CaO

Magnesium 5.88 % Mg 9.75 % MgO

Boron 15.69 % B 50.53 % B₂O₃

Hydrogen 2.93 % H 26.15 % H₂O

Oxygen 65.80 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaMgB₆O₈(OH)₆·3(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1834

Locality:

Caucasus Mountains, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for the composition (water, borate).

Synonym:

ICSD 200417

PDF 42-546

Hydroboracite Image

Images:

Hydroboracite

Comments: White, acicular crystal clusters of hydroboracite.
Location: U. S. Borax Open Pit, Boron, Kern County, California, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Hydroboracite Crystallography

Axial Ratios:

a:b:c =1.7607:1:1.232

Cell Dimensions:

a = 11.769, b = 6.684, c = 8.235, Z = 2; beta = 102.59° V = 632.22 Den(Calc)= 2.17

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/c

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

By Intensity(I/I_o): 5.77(1), 6.68(0.85), 3.32(0.5),

Forms:

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Crystal Structure:

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Sabelli C , Stoppioni A , The Canadian Mineralogist , 16 (1978) p.75-80, Refinement of the crystal structure of hydroboracite

Physical Properties of Hydroboracite

Cleavage:

[???] Perfect

Color:

Colorless, Greenish, White, Light brown, Wine yellow.

Density:

Diaphaniety:

Transparent

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Foliated - Two dimensional platy forms.

Hardness:

2 - Gypsum

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Silky

Streak:

white

Optical Properties of Hydroboracite

Gladstone-Dale:

CI meas= -0.104 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2498,KPDmeas= 0.271,KC= 0.2455

Optical Data:

Biaxial (+), a=1.52-1.523, b=1.534-1.535, g=1.569-1.571, bire=0.0480-0.0490, 2V(Calc)=62-66, 2V(Meas)=60-66. Dispersion relatively weak.

Calculated Properties of Hydroboracite

Electron Density:

r_electron=2.21 gm/cc
note: r_{Hydroboracite}=2.17 gm/cc.

Fermion Index

Fermion Index = 0.03755
Boson Index = 0.96245

Photoelectric:

PE_{Hydroboracite}= 1.56 barns/electron
U=PE_{Hydroboracite} x r_electron= 3.44 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Hydroboracite is Not Radioactive

Hydroboracite Classification

Dana Class:

26.3.6.1 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.3)Dana Type

(26.3.6)Dana Group

26.3.6.1 Hydroboracite CaMgB6O8(OH)6·3(H2O) P 2/c 2/m

Strunz Class:

V/J.03-20 V - Nitrates, Carbonates and Borates

V/J - Chain borates with [B2O4]2- to [B6O10]2-

V/J.03 - Colemanite - Hydroboracite series

V/J.03-10 Colemanite Ca2B6O11·5(H2O) P 2₁/a 2/m

V/J.03-20 Hydroboracite CaMgB6O8(OH)6·3(H2O) P 2/c 2/m

Other Hydroboracite Information

References:

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

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

Hydroboracite

CaMgB6O8(OH)6·3(H2O)
Dana No: 26.3.6.1 Strunz No: V/J.03-20
Locality:

Notes: