Sinhalite Mineral Data

General Sinhalite Information

Chemical Formula:

MgAlBO4

Composition:

Molecular Weight = 126.09 gm

Magnesium 19.28 % Mg 31.96 % MgO

Aluminum 21.40 % Al 40.43 % Al₂O₃

Boron 8.57 % B 27.61 % B₂O₃

Oxygen 50.75 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

MgAl(BO₄)

Environment:

Accessory mineral formed in boron-rich skarns at the contact of limestones with granite or gneiss.

IMA Status:

Valid Species (Pre-IMA) 1952

Locality:

Gem gravels in the Ratnapura district. Sri Lanka. Link to MinDat.org Location Data.

Name Origin:

Named for Sinhala, the Sanskrit name for Ceylon.

Name Pronunciation:

Sinhalite + Pronunciation

Synonym:

ICSD 75942

PDF 25-1379

Sinhalite Image

Images:

Sinhalite

Comments: Crystalline sinhalite in white marble.
Location: Amity, near Warwick, Orange County, New York, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Sinhalite Crystallography

Axial Ratios:

a:b:c =0.4385:1:0.5751

Cell Dimensions:

a = 4.328, b = 9.868, c = 5.676, Z = 4; V = 242.41 Den(Calc)= 3.45

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pbmm

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

By Intensity(I/I_o): 2.14(1), 1.62(0.9), 3.24(0.7),

Physical Properties of Sinhalite

Color:

Brown, Brown pink, Colorless, Yellow, Light pink.

Density:

3.47 - 3.5, Average = 3.48

Diaphaneity:

Transparent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Hardness:

6.5-7 - Pyrite-Quartz

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Sinhalite

Gladstone-Dale:

CI meas= 0.039 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.029 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.201,KPDmeas= 0.199,KC= 0.207
Ncalc = 1.71 - 1.72

Optical Data:

Biaxial (-), a=1.667-1.676, b=1.697-1.704, g=1.705-1.712, bire=0.0360-0.0380, 2V(Calc)=52-54, 2V(Meas)=55.

Pleochroism (x):

brown or pale yellow.

Pleochroism (y):

green or pale brown.

Pleochroism (z):

paler brown, pale greenish brown, or pale pinkish gray.

Calculated Properties of Sinhalite

Electron Density:

Bulk Density (Electron Density)=3.39 gm/cc
note: Specific Gravity of Sinhalite =3.45 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Sinhalite= 1.14 barns/electron
U=PE_Sinhalite x rElectron Density= 3.88 barns/cc.

Radioactivity:

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

Sinhalite Classification

Dana Class:

24.01.01.01 (24)Borates - Anhydrous

(24.01)where (A)2 XO4

(24.01.01)Dana Group

24.01.01.01 Sinhalite MgAlBO4 Pbmm 2/m 2/m 2/m

Strunz Class:

06.AC.05 06 - BORATES

06.A - Monoborates

06.AC -B(O,OH)4, without and with additional anions; 1(T), 1(T)+OH, etc.

06.AC.05 Sinhalite MgAlBO4 Pbmm 2/m 2/m 2/m

Other Sinhalite Information

References:

NAME( AntBidBlaNic5) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic5)

See Also:

Links to other databases for Sinhalite :
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 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - Tradeshop.com - The Rainbow of Gems
17 - WWW-MINCRYST

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

Sinhalite

MgAlBO4
Dana No: 24.01.01.01 Strunz No: 06.AC.05
Locality:

Notes:

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