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).

Name Pronunciation:

Hydroboracite + Pronunciation

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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Forms: ( 0 1 0) ( 1 1 0) ( 1 1 1) ( 1 0 0) ( 0 1 1)

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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:

Diaphaneity:

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
Ncalc = 1.49 - 1.53

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:

Bulk Density (Electron Density)=2.21 gm/cc
note: Specific Gravity of Hydroboracite =2.17 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

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

Radioactivity:

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

Hydroboracite Classification

Dana Class:

26.03.06.01 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.03)Dana Type

(26.03.06)Dana Group

26.03.06.01 Hydroboracite CaMgB6O8(OH)6•3(H2O) P 2/c 2/m

Strunz Class:

06.CB.15 06 - BORATES

06.C - Triborates

06.CB -Ino-triborates

06.CB.15 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)

See Also:

Links to other databases for Hydroboracite :
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 - WWW-MINCRYST

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Ask about Hydroboracite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Hydroboracite

CaMgB6O8(OH)6•3(H2O)
Dana No: 26.03.06.01 Strunz No: 06.CB.15
Locality:

Notes: