Searlesite Mineral Data

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General Searlesite Information

Chemical Formula:

NaBSi2O5(OH)2

Composition:

Molecular Weight = 203.98 gm

Sodium 11.27 % Na 15.19 % Na₂O

Silicon 27.54 % Si 58.91 % SiO₂

Boron 5.30 % B 17.06 % B₂O₃

Hydrogen 0.99 % H 8.83 % H₂O

Oxygen 54.90 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

NaBSi₂O₅(OH)₂

Environment:

Continental alkaline evaporite deposits and alcalic-pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1914

Locality:

Searles Lake, San Bernardino Co., California. Link to MinDat.org Location Data.

Name Origin:

Named after it's locality.

Name Pronunciation:

Searlesite + Pronunciation

Synonym:

ICSD 12134

PDF Jun-37

Searlesite Image

Images:

Searlesite

Comments: Clear, prismatic crystal of Searlesite.
Location: Point of Rocks Mesa. Colfax County, New Mexico, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Searlesite Crystallography

Axial Ratios:

a:b:c =1.1304:1:0.6948

Cell Dimensions:

a = 7.972, b = 7.052, c = 4.9, Z = 2; beta = 93.95° V = 274.82 Den(Calc)= 2.46

Crystal System:

Monoclinic - SphenoidalH-M Symbol (2) Space Group: P 2₁

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

By Intensity(I/I_o): 8.01(1), 4.06(0.5), 3.48(0.4),

Crystal Structure:

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drag2 - RMB Resize/Rotate
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Ghose S , Wan C , American Mineralogist , 61 (1976) p.123-129, Structural chemistry of borosilicates, part II: Searlesite, NaBSi2O5(OH):, Absolute configuration, hydrogen locations, and refinement of the structure, Note: unable to reproduce any of the reported bond lengths

Physical Properties of Searlesite

Cleavage:

{100} Perfect, {010} Distinct, {001} Distinct

Color:

White, Light brown.

Density:

2.45

Diaphaneity:

Transparent to translucent

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

1-2 - Between Talc and Gypsum

Luminescence:

Fluorescent, Short UV=blue green, Long UV=orange.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Searlesite

Gladstone-Dale:

CI meas= 0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.014 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.215,KPDmeas= 0.2159,KC= 0.2181
Ncalc = 1.53 - 1.54

Optical Data:

Biaxial (-), a=1.515-1.524, b=1.531-1.533, g=1.535, bire=0.0110-0.0200

Calculated Properties of Searlesite

Electron Density:

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

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Searlesite= 1.32 barns/electron
U=PE_Searlesite x rElectron Density= 3.23 barns/cc.

Radioactivity:

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

Searlesite Classification

Dana Class:

74.03.05.04 (74)Phyllosilicate Modulated Layers

(74.03)with joined strips

(74.03.05)Na phyllosilicates

74.03.05.01 Natrosilite Na2Si2O5 P 2₁/a 2/m

74.03.05.02 Makatite Na2Si4O8(OH)2•4(H2O) P 2₁/c 2/m

74.03.05.03 Silinaite NaLiSi2O5•2(H2O) A2/n 2/m

74.03.05.04 Searlesite NaBSi2O5(OH)2 P 2₁ 2

Strunz Class:

09.EF.15 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EF -Single nets with 6-membered rings, ± other rings

09.EF.15 Searlesite NaBSi2O5(OH)2 P 2₁ 2

Other Searlesite Information

References:

NAME( Dana8) PHYS. PROP.(www.saint-hilaire.ca;Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Searlesite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - WWW-MINCRYST

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

Searlesite

NaBSi2O5(OH)2
Dana No: 74.03.05.04 Strunz No: 09.EF.15
Locality:

Notes: