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Simmonsite

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Formula:
Na
 
2
Li[AlF
 
6
]
System:MonoclinicColour:Cloudy white, Cream ...
Lustre:Waxy, GreasyHardness:2½ - 3
Name:Named in 1999 by Eugene Edward Foord, Joseph T. O'Connor, John M. Hughes, Stephen J. Sutley, Alexander U. Falster, Arthur E. Soregaroli, Frederick E. Lichte, and Daniel E. Kile in honor of William B. "Skip" Simmons [b. November 5, 1943], University of New Orleans, New Orleans, Louisiana, U.S.A., specialist in the mineralogy and petrology of granitic pegmatites, especially those of Colorado and of NYF type.


Found as lumps (to > 2 cm) of cloudy white interlocking grains which may or may not have a distinct graular appearance. Simmonsite may be distinguished from the many other aluminofluorides with which it may be associated by its orange fluorescence in SW UV only. Cryolithionite fluoresces white to pale creamy white in SW and LW UV and briefly phosphoresces. Commonly associated and/or intergrown with cryolite and minor elpasoite.

Classification of Simmonsite

IMA status:Approved 1999
Strunz 8th edition ID:3/B.03-25
Nickel-Strunz 10th (pending) edition ID:3.CB.15

3 : HALIDES
C : Complex halides
B : Neso-aluminofluorides
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Type Occurrence of Simmonsite

Type Locality:Zapot pegmatite, Gillis Range, Fitting District, Mineral Co., Nevada, USA
General Appearance of Type Material:Low luster waxy masses
Year of Discovery:1992
Geological Setting of type material:Aluminofluoride pods (to 20 cm) in amazonite-rich granite pegmatite
Associated Minerals at type locality:
ZinnwalditeWeberiteTopazThomsenoliteRalstonite
ProsopitePachnoliteFluoriteCryolithioniteCryolite
Amazonite

Physical Properties of Simmonsite

Lustre:Waxy, Greasy
Diaphaneity (Transparency):Translucent
Comment:Low luster waxy or low luster greasy
Colour:Cloudy white, Cream white, pale buff
Streak:White
Hardness (Mohs):2½ - 3
Tenacity:Brittle
Cleavage:None Observed
Fracture:Irregular/Uneven
Density (measured):3.05 g/cm3
Density (calculated):3.06 g/cm3

Crystallography of Simmonsite

Crystal System:Monoclinic
Cell Parameters:a = 7.5006Å, b = 7.474Å, c = 7.503Å
β = 90.848°
Ratio:a:b:c = 1.004 : 1 : 1.004
Unit Cell Volume:V 420.57 ų (Calculated from Unit Cell)
Z:4
Morphology:Crystals not observed
Twinning:Abundant polysynthetic twinning
Comment:P21 or P21/m
X-Ray Powder Diffraction:
d-spacingIntensity
4.33 (100)
3.78 (10)
3.36 (5)
2.65 (60)
2.37 (15)
2.25 (70)
2.18 (50)
2.158 (40)
2.076 (5)
2.008 (10)
1.877 (90)
1.526 (25)

Optical Data of Simmonsite

Type:Biaxial
RI values: nα = 1.359 nβ = 1.359 nγ = 1.359
Birefringence:0.0009
Maximum Birefringence:δ = 0.000

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:r < v weak
Optical Extinction:Nearly isotropic
Pleochroism:Non-pleochroic

Chemical Properties of Simmonsite

Formula:
Na
 
2
Li[AlF
 
6
]
Simplified for copy/paste:Na2Li[AlF6]
Essential elements:Al, F, Li, Na
All elements listed in formula:Al, F, Li, Na

Relationship of Simmonsite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
3.CB.05Cryolithionite
Na
 
3
Li
 
3
[AlF
 
6
]
 
2
3.CB.15Cryolite
Na
 
3
[AlF
 
6
]
3.CB.15Elpasolite
NaK
 
2
[AlF
 
6
]
3.CB.20Colquiriite
CaLi[AlF
 
6
]
3.CB.25Weberite
Na
 
2
Mg[AlF
 
6
]F
3.CB.30Karasugite
SrCa[Al(F,OH)
 
7
]
3.CB.35Usovite
Ba
 
2
CaMgAl
 
2
F
 
14
3.CB.40Pachnolite
NaCa[AlF
 
6
] · H
 
2
O
3.CB.40Thomsenolite
NaCa[AlF
 
6
] · H
 
2
O
3.CB.45Carlhintzeite
Ca
 
2
[AlF
 
6
]F · H
 
2
O
3.CB.50Yaroslavite
Ca
 
3
Al
 
2
F
 
10
(OH)
 
2
· H
 
2
O

Other Names for Simmonsite

Synonyms:
IMA1997-045
Other Languages:
German:Simmonsit
Russian:Симмонсит
Spanish:Simmonsita

Other Information

Fluorescence in UV light:Fluoresces moderately bright orange in Short Wave UV, but the fluorescent response may be patchy due to alterations. May be associated with cryolithionite which fluoresces white to pale creamy white in both Short Wave and Long Wave.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Simmonsite

Reference List:

- +
Eugene Edward Foord, Joseph T. O'Connor, John M. Hughes, Stephen J. Sutley, Alexander U. Falster, Arthur E. Soregaroli, Frederick E. Lichte, and Daniel E. Kile (1999) Simmonsite, Na2LiAlF6, a New Mineral from the Zapot amazonite-topaz-zinnwaldite pegmatite, Hawthorne, Nevada, U.S.A., American Mineralogist 84: 769-772.

Internet Links for Simmonsite

Search Engines:
  • Look for Simmonsite on Google
  • Look for Simmonsite images on Google
  • External Links:
  • Look for Simmonsite on Webmineral
  • Look for Simmonsite on Athena Mineralogy
  • Look for Simmonsite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Simmonsite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Search for Simmonsite on Well-Arranged Molecules
  • Fine Minerals from Weinrich Minerals, Inc.
  • rare and unusual minerals mainly crystallized
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  • Lapis Mineral Magazin
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  • Find Simmonsite on www.crystalclassics.co.uk
  • Wilensky Fine Minerals
  • Fine minerals from bisbeeborn.com
  • Localities for Simmonsite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    USA
     
    • Nevada
      • Mineral Co.
        • Fitting District
          • Gillis Range
    Mineralogical Record: 31: 204.
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