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 % K2 O
Sodium 12.56 % Na 16.93 % Na2 O
Sulfur 20.02 % S 49.99 % SO3
Oxygen 39.96 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
K2.25 Na1.75 (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 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 Scalenohedral H-M Symbol (3 2/m) Space Group: P 3 m
X Ray Diffraction:
By Intensity(I/Io ): 2.85(1), 2.09(0.9), 2.97(0.9),
Forms:
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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:
PEAphthitalite = 4.16 barns/electronU=PEAphthitalite 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 3 m 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 3 m 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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Aphthitalite
(K,Na)3Na(SO4)2
Dana No: 28.02.02.01 Strunz No: 07.AC.35
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