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|System:||Monoclinic||Colour:||Cloudy white, Cream ...|
|Lustre:||Waxy, Greasy||Hardness:||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:|
Physical Properties of Simmonsite
|Comment:||Low luster waxy or low luster greasy|
|Colour:||Cloudy white, Cream white, pale buff|
|Hardness (Mohs):||2½ - 3|
|Density (measured):||3.05 g/cm3|
|Density (calculated):||3.06 g/cm3|
Crystallography of Simmonsite
|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 Å³ (Calculated from Unit Cell)|
|Morphology:||Crystals not observed|
|Twinning:||Abundant polysynthetic twinning|
|Comment:||P21 or P21/m|
|X-Ray Powder Diffraction:|
Optical Data of Simmonsite
|RI values:||nα = 1.359 nβ = 1.359 nγ = 1.359|
|Maximum Birefringence:||δ = 0.000|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Dispersion:||r < v weak|
|Optical Extinction:||Nearly isotropic|
Chemical Properties of Simmonsite
|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):|
Other Names for Simmonsite
|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
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
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.