Log InRegister
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreOur ScienceMindat Newsletter [Free Download]Contact Us
Donate to MindatSponsor a PageCorporate SponsorshipSponsored Pages
Learning CenterWhat Is a Mineral?The Most Common Minerals on EarthInformation for EducatorsMindat ArticlesMindat Newsletter [Free Download]The ElementsThe Mineral Quiz
Search FormMinerals by PropertiesMinerals by ChemistryMineral Visual ExplorerAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDMinerals by CountryAlphabetical Mineral IndexAlphabetical Locality SearchMineral Association SearchList of CountriesLocalities Near MePhoto SearchSearch ArticlesSearch GlossaryThe Rock H. Currier Digital LibraryMore Search Options
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
MineralsPetrologyFossilsMeteoritesGeologic Time
Mining CompaniesStatisticsMineral MuseumsClubs & OrganizationsMineral Shows & EventsDevice SettingsTime Machine
Read DiscussionsIdentification Request
Photo SearchPhoto GalleriesSearch by ColourPhoto Colour ExplorerNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Fluorapophyllite-(NH4)

A valid IMA mineral species - pending publication
This page is currently not sponsored. Click here to sponsor this page.
Hide all sections | Show all sections

About Fluorapophyllite-(NH4)Hide

Formula:
NH4Ca4(Si8O20)F · 8H2O
Colour:
Colourless to light pink
Lustre:
Vitreous, Pearly
Hardness:
4½ - 5
Specific Gravity:
2.325 (Calculated)
Crystal System:
Tetragonal
Name:
Named for being the ammonium (NH4) analogue of fluorapophyllite-(K).
Ammonium dominant fluorapophyllite. The NH4 analogue of fluorapophyllite-(K).

Unique combination of elements.

First group member with essential ammonium.


Name EncodingHide

Formatted:
fluorapophyllite-(NH4)
HTML:
fluorapophyllite-(NH<sub>4</sub>)
LaTeX:
fluorapophyllite-(NH\$\_4\$)

Unique IdentifiersHide

Mindat ID:
53993
Long-form identifier:
mindat:1:1:53993:3

Similar NamesHide

FluorapophylliteA synonym
Fluorapophyllite-(Cs)A valid IMA mineral speciesCsCa4(Si8O20)F · 8H2O
Fluorapophyllite-(K)A valid IMA mineral species - grandfatheredKCa4(Si8O20)(F,OH) · 8H2O
Fluorapophyllite-(K) - Hydroxyapophyllite-(K) SeriesA solid-solution series between two end-member minerals
Fluorapophyllite-(Na)A valid IMA mineral speciesNaCa4(Si8O20)F · 8H2O

IMA Classification of Fluorapophyllite-(NH4)Hide

Classification of Fluorapophyllite-(NH4)Hide

9.EA.

9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

SymbolSourceReference for Standard
Fapo-NH4IMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43
FapoThe Canadian Mineralogist (2019)The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download

Physical Properties of Fluorapophyllite-(NH4)Hide

Vitreous, Pearly
Transparency:
Transparent
Colour:
Colourless to light pink
Streak:
White
Hardness:
4½ - 5 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {001}
Fracture:
Irregular/Uneven
Density:
2.325 g/cm3 (Calculated)

Optical Data of Fluorapophyllite-(NH4)Hide

Type:
Uniaxial (+)
RI values:
nω = 1.5414(5) nε = 1.5393(8)
Max. Birefringence:
δ = 0.002
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.

Surface Relief:
None to Very Low
Relative to Canada balsam mounting medium (n ≈ 1.537).

This shows the grain boundary and Becke line effect under plane-polarised light, based on the contrast between this mineral's average refractive index and the mounting medium. It does not take into account mineral colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic (convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis centred and vertical. The coloured rings are isochromatics, computed with the same physics as the Michel-Lévy bar above; the dark cross is the isogyre.

For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Non-pleochroic

Chemistry of Fluorapophyllite-(NH4)Hide

Mindat Formula:
NH4Ca4(Si8O20)F · 8H2O
Element Weights:
Element% weight
O50.554 %
Si25.355 %
Ca18.091 %
H2.275 %
F2.144 %
N1.581 %

Calculated from ideal end-member formula.
O
Si
Ca
H
F
N

Crystallography of Fluorapophyllite-(NH4)Hide

Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
P4/mnc
Cell Parameters:
a = 8.99336(9) Å, c = 15.7910(3) Å
Ratio:
a:c = 1 : 1.756
Unit Cell V:
1277.18 ų
Z:
2
Morphology:
Forms {110}, {101} and {001}

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 4a: Earth’s earliest continental crust>4.4-3.0
20 : Acidic volcanic rocks

Type Occurrence of Fluorapophyllite-(NH4)Hide

General Appearance of Type Material:
Clusters, aggregates or crystalline crusts consisting of individual, well-developed crystals up to 4 mm in size
Place of Conservation of Type Material:
In the collections of the Department of Mineralogy and Petrology, National Museum in Prague, Cirkusová 1740, 19300 Prague 9, Czech Republic, catalogue number P1P 44/2019
Geological Setting of Type Material:
In cavities of quartz–illite–saponite–tobelite xenolith embedded in pyroxene andesite
Associated Minerals at Type Locality:

Synonyms of Fluorapophyllite-(NH4)Hide

Other Language Names for Fluorapophyllite-(NH4)Hide

Relationship of Fluorapophyllite-(NH4) to other SpeciesHide

Other Members of Apophyllite Group:
Fluorapophyllite-(Cs)CsCa4(Si8O20)F · 8H2OTet. 4/mmm(4/m2/m2/m) : P4/mnc
Fluorapophyllite-(K)KCa4(Si8O20)(F,OH) · 8H2OTet. 4/mmm(4/m2/m2/m) : P4/mnc
Fluorapophyllite-(Na)NaCa4(Si8O20)F · 8H2OOrth.
Hydroxyapophyllite-(K)KCa4(Si8O20)(OH,F) · 8H2OTet. 4/mmm(4/m2/m2/m)
Hydroxyapophyllite-(NH4)(NH4)Ca4(Si8O20)(OH)(H2O)8Tet. 4/mmm(4/m2/m2/m)
Hydroxymcglassonite-(K)KSr4Si8O20(OH) · 8H2OTet.

Common AssociatesHide

Associations Based on Photo Data:
1 photo of Fluorapophyllite-(NH4) associated with CalciteCaCO3

Related Minerals - Strunz-mindat GroupingHide

9.EA.Hydroxymcglassonite-(K)KSr4Si8O20(OH) · 8H2OTet.
9.EA.Miyawakiite-(Y)◻Y4Fe2(Si8O20)(CO3)4(H2O)3Tet. 4/mmm(4/m2/m2/m) : I4/mcm
9.EA.Bussyite-(Y)(Y,REE,Ca)3(Na,Ca)6MnSi9Be5(O,OH,F)34Mon. 2 : B2
9.EA.Hydroxyapophyllite-(NH4)(NH4)Ca4(Si8O20)(OH)(H2O)8Tet. 4/mmm(4/m2/m2/m)
9.EA.05GillespiteBaFe2+Si4O10Tet. 4/mmm(4/m2/m2/m) : P4/ncc
9.EA.05CuprorivaiteCaCuSi4O10Tet. 4/mmm(4/m2/m2/m) : P4/ncc
9.EA.05WesselsiteSrCuSi4O10Tet. 4/mmm(4/m2/m2/m) : P4/ncc
9.EA.05EffenbergeriteBaCuSi4O10Tet. 4/mmm(4/m2/m2/m) : P4/ncc
9.EA.07Fluorapophyllite-(Cs)CsCa4(Si8O20)F · 8H2OTet. 4/mmm(4/m2/m2/m) : P4/mnc
9.EA.10EkaniteCa2ThSi8O20Tet. 422 : I422
9.EA.15Fluorapophyllite-(Na)NaCa4(Si8O20)F · 8H2OOrth.
9.EA.15Fluorapophyllite-(K)KCa4(Si8O20)(F,OH) · 8H2OTet. 4/mmm(4/m2/m2/m) : P4/mnc
9.EA.15Hydroxyapophyllite-(K)KCa4(Si8O20)(OH,F) · 8H2OTet. 4/mmm(4/m2/m2/m)
9.EA.20MagadiiteNa2Si14O29 · 11H2OOrth. mm2 : Fdd2
9.EA.25DalyiteK2ZrSi6O15Tric. 1 : P1
9.EA.25DavaniteK2TiSi6O15Tric.
9.EA.30Sazhinite-(La)Na3La[Si6O15] · 2H2OOrth. mm2 : Pmm2
9.EA.30Sazhinite-(Ce)Na3CeSi6O15 · 2H2OOrth. mm2 : Pmm2
9.EA.35ArmstrongiteCaZr[Si6O15] · 3H2OMon. 2/m : B2/m
9.EA.40OkeniteCa10Si18O46 · 18H2OTric. 1 : P1
9.EA.45Perettiite-(Y)Y2Mn4FeSi2B8O24Orth. mmm(2/m2/m2/m) : Pmna
9.EA.45NekoiteCa3Si6O15 · 7H2OTric. 1 : P1
9.EA.45Badakhshanite-(Y)Y2Mn4Al(Si2B7BeO24)Orth. mmm(2/m2/m2/m) : Pnma
9.EA.47ShlykoviteKCa[Si4O9(OH)] · 3H2OMon. 2/m : P21/c
9.EA.50DiegogattaiteNa2CaCu2Si8O20 · H2OMon. 2/m : B2/m
9.EA.50CavansiteCa(VO)Si4O10 · 4H2OOrth. mmm(2/m2/m2/m)
9.EA.52YangitePbMnSi3O8 · H2OTric. 1 : P1
9.EA.55PentagoniteCa(VO)Si4O10 · 4H2OOrth. mm2
9.EA.60PenkvilksiteNa4Ti2Si8O22 · 4H2OOrth. mmm(2/m2/m2/m) : Pbcn
9.EA.60TumchaiteNa2Zr(Si4O11) · 2H2OMon. 2/m : P21/c
9.EA.65NabesiteNa2BeSi4O10 · 4H2OOrth. 222 : P212121
9.EA.70Ajoite(K,Na)Cu7AlSi9O24(OH)6 · 3H2OTric.
9.EA.75ZeravshaniteNa2Cs4Zr3[Si18O45]*2H2OMon. 2/m : B2/b
9.EA.80Bussyite-(Ce)(Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4Mon. 2/m : B2/b
9.EA.85PlumbophyllitePb2Si4O10 · H2OOrth. mmm(2/m2/m2/m) : Pbcn

Fluorescence of Fluorapophyllite-(NH4)Hide

Not fluorescent

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for Fluorapophyllite-(NH4)Hide

References for Fluorapophyllite-(NH4)Hide

Localities for Fluorapophyllite-(NH4)Hide

Showing 1 localities.

This 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.
Hide all sections | Show all sections

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Slovakia (TL)
 
  • Prešov Region
    • Vranov nad Topľou District
      • Vechec
Števko et al. (2020)
 
and/or  
Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: November 1, 2026 05:12:40 Page updated: October 8, 2026 19:10:52
Go to top of page