Colemanite Mineral Data

General Colemanite Information

Chemical Formula:

Ca2B6O11•5(H2O)

Composition:

Molecular Weight = 411.09 gm

Calcium 19.50 % Ca 27.28 % CaO

Boron 15.78 % B 50.81 % B₂O₃

Hydrogen 2.45 % H 21.91 % H₂O

Oxygen 62.27 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂B₆O₁₁•5(H₂O)

Environment:

Lacusterine limestone hosted borate deposits.

IMA Status:

Valid Species (Pre-IMA) 1884

Locality:

Furnace Creek district, Death Valley, Inyo Co. California. Link to MinDat.org Location Data.

Name Origin:

After William T. Coleman, owner of the Death Valley, California mine where this species was first found.

Name Pronunciation:

Colemanite + Pronunciation

Synonym:

ICSD 75921

Neocolmanite

PDF 33-267

Colemanite Image

Images:

Colemanite

Comments: Coarsely crystalline colemanite, in part, covered with minute acicular crystals of strontianite.
Location: Boraxo #3 pit, Death Valley, California, USA. Scale: 30 cm.
© Dave Barthelmy

Images:

Colemanite

Comments: Large crystals of brown colemanite with second generation of absolutely clear and gemmy (colorless) colemanite. Intensely fluorescent in long and short UV..
Location: Mustafakemalpascha Mine, West-Anatolia Turkey. Scale: Crystal size: 1.3 x 1 cm.
© Fabre Minerals

Colemanite Crystallography

Axial Ratios:

a:b:c =0.7761:1:0.5417

Cell Dimensions:

a = 8.743, b = 11.264, c = 6.102, Z = 2; beta = 110.116° V = 564.27 Den(Calc)= 2.42

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): 3.13(1), 3.85(0.5), 5.64(0.5),

Forms:

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Forms: ( 1 2 1) ( 1 1 1) ( 1 0 0) ( 1 1 1) ( 1 1 0) ( 0 0 1)

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Crystal Structure:

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Burns P C , Hawthorne F C , The Canadian Mineralogist , 31 (1993) p.297-304, Hydrogen bonding in colemanite: An X-ray and structure-energy study

Physical Properties of Colemanite

Cleavage:

{010} Perfect, {001} Distinct

Color:

Colorless, Gray, Gray white, Yellowish white, White.

Density:

2.42

Diaphaneity:

Transparent to translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Blocky - Crystal shape tends to be equant (e.g. feldspars).

Habit:

Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

4.5 - Between Fluorite and Apatite

Luminescence:

Fluorescent, Short UV=yellow, blue white, Long UV=yellow, blue white.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Colemanite

Gladstone-Dale:

CI meas= -0.024 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.024 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2468,KPDmeas= 0.2468,KC= 0.241
Ncalc = 1.58

Optical Data:

Biaxial (+), a=1.586, b=1.592, g=1.614, bire=0.0280, 2V(Calc)=56, 2V(Meas)=55-56. Dispersion relatively weak.

Calculated Properties of Colemanite

Electron Density:

Bulk Density (Electron Density)=2.45 gm/cc
note: Specific Gravity of Colemanite =2.42 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Colemanite= 2.61 barns/electron
U=PE_Colemanite x rElectron Density= 6.38 barns/cc.

Radioactivity:

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

Colemanite Classification

Dana Class:

26.03.05.01 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.03)Dana Type

(26.03.05)Dana Group

26.03.05.01 Colemanite Ca2B6O11•5(H2O) P 2₁/a 2/m

Strunz Class:

06.CB.10 06 - BORATES

06.C - Triborates

06.CB -Ino-triborates

06.CB.10 Colemanite Ca2B6O11•5(H2O) P 2₁/a 2/m

Other Colemanite Information

References:

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

See Also:

Links to other databases for Colemanite :
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 - Glendale Community College
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineral and Gemstone Kingdom
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - Philatelic Mineralogy
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - WWW-MINCRYST

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Ask about Colemanite 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 Colemanite Specimen Label here :

Colemanite

Ca2B6O11•5(H2O)
Dana No: 26.03.05.01 Strunz No: 06.CB.10
Locality:

Notes: