Tunellite Mineral Data

General Tunellite Information

Chemical Formula:

SrB6O9(OH)2•3(H2O)

Composition:

Molecular Weight = 384.54 gm

Strontium 22.79 % Sr 26.95 % SrO

Boron 16.87 % B 54.31 % B₂O₃

Hydrogen 2.10 % H 18.74 % H₂O

Oxygen 58.25 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

SrB₆O₉(OH)₂•3(H₂O)

Environment:

Borate deposits.

IMA Status:

Approved IMA 1961

Locality:

U. S. Borax open pit, Boron, Kern Co., California. Link to MinDat.org Location Data.

Name Origin:

Named for George Tunnel (1900-1996), U. S. Mineralogist.

Name Pronunciation:

Tunellite + Pronunciation

Synonym:

Balavinskite ?

ICSD 15479

PDF 14-616

Tunellite Image

Images:

Tunellite

Comments: Clear, prismatic crystals of tunellite on matrix.
Location: Death Valley, Inyo County, California, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Tunellite Crystallography

Axial Ratios:

a:b:c =1.7521:1:1.2095

Cell Dimensions:

a = 14.39, b = 8.213, c = 9.934, Z = 4; beta = 114.067° V = 1,071.99 Den(Calc)= 2.38

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 6.57(1), 5.135(0.3), 6.97(0.25),

Crystal Structure:

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drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
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Clark J R , American Mineralogist , 49 (1964) p.1549-1568, The crystal structure of tunellite, SrB6O9(OH)2.3H2O

View Additional jPOWD Structure files for Tunellite
[1]

Physical Properties of Tunellite

Cleavage:

{100} Perfect, {001} Distinct

Color:

Colorless.

Density:

2.4

Diaphaneity:

Transparent

Habit:

Nodular - Tuberose forms having irregular protuberances over the surface.

Habit:

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

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

2.5 - Finger Nail

Luminescence:

Fluorescent, Short UV=butter yellow, Long UV=butter yellow.

Luster:

Vitreous - Pearly

Streak:

white

Optical Properties of Tunellite

Gladstone-Dale:

CI meas= -0.026 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.035 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2272,KPDmeas= 0.2253,KC= 0.2196
Ncalc = 1.52 - 1.53

Optical Data:

Biaxial (+), a=1.519, b=1.534, g=1.569, bire=0.0500

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Tunellite

Electron Density:

Bulk Density (Electron Density)=2.35 gm/cc
note: Specific Gravity of Tunellite =2.40 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Tunellite= 24.87 barns/electron
U=PE_Tunellite x rElectron Density= 58.36 barns/cc.

Radioactivity:

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

Tunellite Classification

Dana Class:

26.06.06.02 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.06)Dana Type

(26.06.06)Dana Group

26.06.06.01 Nobleite CaB6O9(OH)2•3(H2O) P 2₁/a 2/m

26.06.06.02 Tunellite SrB6O9(OH)2•3(H2O) P 2₁/a 2/m

Strunz Class:

06.FC.05 06 - BORATES

06.F - Hexaborates

06.FC -Phyllo-hexaborates

06.FC.05 Balavinskite? Sr2B6O11•4(H2O) Mono ? Mono

06.FC.05 Nobleite CaB6O9(OH)2•3(H2O) P 2₁/a 2/m

06.FC.05 Tunellite SrB6O9(OH)2•3(H2O) P 2₁/a 2/m

Other Tunellite 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 Tunellite :
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

Search for Tunellite using:

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Ask about Tunellite 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 Tunellite Specimen Label here :

Tunellite

SrB6O9(OH)2•3(H2O)
Dana No: 26.06.06.02 Strunz No: 06.FC.05
Locality:

Notes: