Aphthitalite Mineral Data

General Aphthitalite Information

Chemical Formula:

(K,Na)3Na(SO4)2

Composition:

Molecular Weight = 320.33 gm

Potassium 27.46 % K 33.08 % K₂O

Sodium 12.56 % Na 16.93 % Na₂O

Sulfur 20.02 % S 49.99 % SO₃

Oxygen 39.96 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K_2.25Na_1.75(SO₄)₂

Environment:

1. Incrustations in fumaroles of volcanos. 2. Small crystals in marine and continental evaporite deposits.

IMA Status:

Valid Species (Pre-IMA) 1813

Locality:

Douglashall near Strassfurt, Germany. Link to MinDat.org Location Data.

Name Origin:

Named from the Greek for "unalterable" and "salt" in allusion to its stability in air.

Name Pronunciation:

Aphthitalite + Pronunciation

Synonym:

Aphthalose

Glaserite

ICSD 26014

PDF 20-928

Vesuvian Salt

Aphthitalite Image

Images:

Aphthitalite

Comments: Aphthitalite crystals.
Location: Searles Lake, San Bernardino County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Aphthitalite Crystallography

Axial Ratios:

a:c = 1:1.29026

Cell Dimensions:

a = 5.65, c = 7.29, Z = 1; V = 201.54 Den(Calc)= 2.64

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: P 3m

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

By Intensity(I/I_o): 2.85(1), 2.09(0.9), 2.97(0.9),

Forms:

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

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Crystal Structure:

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Okada K , Ossaka J , Acta Crystallographica, Section B , 36 (1980) p.919-921, Structures of potassium sodium sulphate and tripotassium sodium disulphate

Physical Properties of Aphthitalite

Cleavage:

{1011} Good

Color:

Blue, Colorless, Green, Gray, Gray blue.

Density:

2.7

Diaphaneity:

Transparent to Opaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

3 - Calcite

Luminescence:

Fluorescent, Short UV=weak yellow, Long UV=butter yellow.

Luster:

Vitreous - Resinous

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Aphthitalite

Gladstone-Dale:

CI meas= 0.017 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.005 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1865,KPDmeas= 0.1823,KC= 0.1855
Ncalc = 1.49 - 1.5

Optical Data:

Uniaxial (+), w=1.487-1.491, e=1.492-1.499, bire=0.0050-0.0080.

Calculated Properties of Aphthitalite

Electron Density:

Bulk Density (Electron Density)=2.60 gm/cc
note: Specific Gravity of Aphthitalite =2.64 gm/cc.

Fermion Index:

Fermion Index = 0.001726293
Boson Index = 0.998273707

Photoelectric:

PE_Aphthitalite= 4.16 barns/electron
U=PE_Aphthitalite x r_electron= 10.84 barns/cc.

Radioactivity:

GRapi = 390.88 (Gamma Ray American Petroleum Institute Units)
Concentration of Aphthitalite per GRapi unit = 0.26 (%)

Estimated Radioactivity from Aphthitalite - barely detectable

Aphthitalite Classification

Dana Class:

28.02.02.01 (28)Anhydrous Acid and Sulfates

(28.02)(A+)2 XO4

(28.02.02)Dana Group

28.02.02.01 Aphthitalite (K,Na)3Na(SO4)2 P 3m 3 2/m

Strunz Class:

07.AC.35 07 - SULFATES (SELENATES, TELLURATES)

07.A - Sulfates (selenates, etc.) without Additional Anions, without H2O

07.AC -With medium-sized and large cations

07.AC.35 Aphthitalite (K,Na)3Na(SO4)2 P 3m 3 2/m

Other Aphthitalite Information

References:

NAME( Dana7) PHYS. PROP.(Collectors Book of Fluorescent Minerals) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Aphthitalite :
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
15 - WWW-MINCRYST

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Ask about Aphthitalite here :
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Print or Cut-and-Paste your Aphthitalite Specimen Label here :

Aphthitalite

(K,Na)3Na(SO4)2
Dana No: 28.02.02.01 Strunz No: 07.AC.35
Locality:

Notes: