Wightmanite Mineral Data

General Wightmanite Information

Chemical Formula:

Mg5(BO3)O(OH)5•2(H2O)

Composition:

Molecular Weight = 317.40 gm

Magnesium 38.29 % Mg 63.49 % MgO

Boron 3.41 % B 10.97 % B₂O₃

Hydrogen 2.86 % H 25.54 % H₂O

Oxygen 55.45 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₅(BO₃)O(OH)₅•2(H₂O)

Environment:

Contact metamorphosed limestone.

IMA Status:

Approved IMA 1962

Locality:

Crestmore Quarry, 5 miles NW of Riverside, Riverside Co., California. Link to MinDat.org Location Data.

Name Origin:

Named for Randall H. Wightman (1915-1969), Director of Exploration and Mining of the Riverside Cement Co., Riverside, California, USA.

Name Pronunciation:

Wightmanite + Pronunciation

Synonym:

ICSD 34371

PDF 14-640

Wightmanite Image

Images:

Wightmanite

Comments: Tan silky prismatic wightmanite in pale blue calcite.
Location: Crestmore Quarry, Riverside County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Wightmanite Crystallography

Axial Ratios:

a:b:c =4.3391:1:5.8575

Cell Dimensions:

a = 13.46, b = 3.102, c = 18.17, Z = 4; beta = 91.6° V = 758.35 Den(Calc)= 2.78

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: I2/m

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

By Intensity(I/I_o): 9.07(1), 10.7(1), 3.03(0.3),

Physical Properties of Wightmanite

Cleavage:

{010} Perfect, {100} Distinct

Color:

Colorless, Light green.

Density:

2.6

Diaphaneity:

Transparent

Hardness:

5.5 - Knife Blade

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Wightmanite

Gladstone-Dale:

CI meas= 0.032 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.095 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2149,KPDmeas= 0.2297,KC= 0.2374
Ncalc = 1.62 - 1.66

Optical Data:

Biaxial (-), a=1.585, b=1.603, g=1.604, bire=0.0190, 2V(Calc)=26, 2V(Meas)=33.

Calculated Properties of Wightmanite

Electron Density:

Bulk Density (Electron Density)=2.65 gm/cc
note: Specific Gravity of Wightmanite =2.60 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Wightmanite= 0.96 barns/electron
U=PE_Wightmanite x rElectron Density= 2.54 barns/cc.

Radioactivity:

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

Wightmanite Classification

Dana Class:

26.01.02.01 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.01)Dana Type

(26.01.02)Dana Group

26.01.02.01 Wightmanite Mg5(BO3)O(OH)5•2(H2O) I2/m 2/m

Strunz Class:

06.AB.55 06 - BORATES

06.A - Monoborates

06.AB -BO3, with additional anions; 1(D) + OH, etc.

06.AB.55 Shabynite Mg5(BO3)Cl2(OH)5•4(H2O) Unk. Mono

06.AB.55 Wightmanite Mg5(BO3)O(OH)5•2(H2O) I2/m 2/m

Other Wightmanite Information

References:

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

See Also:

Links to other databases for Wightmanite :
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

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

Wightmanite

Mg5(BO3)O(OH)5•2(H2O)
Dana No: 26.01.02.01 Strunz No: 06.AB.55
Locality:

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