Wightmanite Mineral Data

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:

Metamorphosed limestone.

IMA Status:

Approved IMA 1962

Locality:

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

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 - PrismaticH-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

Diaphaniety:

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

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:

r_electron=2.65 gm/cc
note: r_Wightmanite=2.60 gm/cc.

Fermion Index

Fermion Index = 0.04533
Boson Index = 0.95467

Photoelectric:

PE_Wightmanite= 0.96 barns/electron
U=PE_Wightmanite x r_electron= 2.54 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Wightmanite is Not Radioactive

Wightmanite Classification

Dana Class:

26.1.2.1 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.1)Dana Type

(26.1.2)Dana Group

26.1.2.1 Wightmanite Mg5(BO3)O(OH)5·2(H2O) I2/m 2/m

Strunz Class:

V/G.06-20 V - Nitrates, Carbonates and Borates

V/G - "Insel" borates [BO3]3- "inseln"

V/G.06 - Berborite - Qilianshanite series

V/G.06-10 Berborite Be2(BO3)(OH,F)·(H2O) P 6₃ 6

V/G.06-20 Wightmanite Mg5(BO3)O(OH)5·2(H2O) I2/m 2/m

V/G.06-30 Shabynite Mg5(BO3)Cl2(OH)5·4(H2O) Unk. Mono

V/G.06-40 Canavesite Mg2(CO3)(HBO3)·5(H2O) P 2/m 2/m

V/G.06-50 Sakhaite Ca3Mg(BO3)2(CO3)·0.36(H2O) F 4₁32 4 3 2

V/G.06-60 Qilianshanite NaH4(CO3)(BO3)·2(H2O) C 2 2

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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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

Wightmanite

Mg5(BO3)O(OH)5·2(H2O)
Dana No: 26.1.2.1 Strunz No: V/G.06-20
Locality:

Notes: