Borax Mineral Data

Borax Mineral Data +

General Borax Information

Chemical Formula:

Na2B4O5(OH)4·8(H2O)

Composition:

Molecular Weight = 381.37 gm

Sodium 12.06 % Na 16.25 % Na₂O

Boron 11.34 % B 36.51 % B₂O₃

Hydrogen 5.29 % H 47.24 % H₂O

Oxygen 71.32 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₂(B₄O₅)(OH)₄·8(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1753

Locality:

Link to MinDat.org Location Data.

Name Origin:

From the Arabic buraq, for "white."

Synonym:

ICSD 30506

PDF 33-1215

Tincal

Borax Image

Images:

Borax

Comments: Translucent crystal of borax preserved in oil to prevent dehydration to tincalconite.
Location: Searles Lake, San Bernardino County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Borax Crystallography

Axial Ratios:

a:b:c =1.1109:1:1.1873

Cell Dimensions:

a = 11.858, b = 10.674, c = 12.674, Z = 4; beta = 106.583° V = 1,537.46 Den(Calc)= 1.65

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: A2/a

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

By Intensity(I/I_o): 4.82(1), 5.68(0.9), 2.56(0.65),

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Forms: [ 1 1 1] [ 1 1 2] [ 0 1 0] [ 1 0 0] [ 1 1 0] [ 0 0 1]

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Physical Properties of Borax

Cleavage:

[100] Perfect, [110] Perfect

Color:

Blue, Colorless, Green, Gray, Gray white.

Density:

1.7 - 1.72, Average = 1.71

Diaphaniety:

Translucent to opaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

2-2.5 - Gypsum-Finger Nail

Luminescence:

None.

Luster:

Greasy (Oily)

Streak:

white

Optical Properties of Borax

Gladstone-Dale:

CI meas= -0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.039 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2805,KPDmeas= 0.2707,KC= 0.27

Optical Data:

Biaxial (-), a=1.447, b=1.469-1.47, g=1.472, bire=0.0250, 2V(Calc)=32-40, 2V(Meas)=39-40. Dispersion r > v distinct.

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Borax

Electron Density:

r_electron=1.78 gm/cc
note: r_Borax=1.71 gm/cc.

Fermion Index

Fermion Index = 0.02291
Boson Index = 0.97709

Photoelectric:

PE_Borax= 0.47 barns/electron
U=PE_Borax x r_electron= 0.84 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Borax is Not Radioactive

Borax Classification

Dana Class:

26.4.1.1 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.4)Dana Type

(26.4.1)Dana Group

26.4.1.1 Borax Na2B4O5(OH)4·8(H2O) A2/a 2/m

Strunz Class:

V/H.10-30 V - Nitrates, Carbonates and Borates

V/H - Group borates. Planary and tetrahedral groups [B3O5]1- to [B6O10]2-

V/H.10 - Diomignite - Borax series

V/H.10-10 Diomignite Li2B4O7 I 4₁cd 4mm

V/H.10-20 Tincalconite Na6[B4O5(OH)4]3·8(H2O) R 32 3 2

V/H.10-30 Borax Na2B4O5(OH)4·8(H2O) A2/a 2/m

Other Borax Information

References:

NAME( Sinkankas66) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

See Also:

Links to other databases for Borax :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - MinMax(Deutsch)
12 - MinMax(English)
13 - Mineral and Gemstone Kingdom
14 - Mineralienatlas (Deutsch)
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - WWW-MINCRYST

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Borax

Na2B4O5(OH)4·8(H2O)
Dana No: 26.4.1.1 Strunz No: V/H.10-30
Locality:

Notes: