Amicite
A valid IMA mineral species
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About Amicite
Giovanni Battista Amici
Formula:
K2Na2Al4Si4O16 · 5H2O
Colour:
Colorless
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.06 - 2.23
Crystal System:
Monoclinic
Member of:
Name:
Named in 1979 for Giovanni Battista Amici (1786-1863), physicist, optician and inventor of the Amici lens.
Unique Identifiers
Mindat ID:
199
Long-form identifier:
mindat:1:1:199:9
IMA Classification of Amicite
Approved
IMA Formula:
K2Na2(Al4Si4O16) · 5H2O
Classification of Amicite
9.GC.05
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
C : Chains of doubly-connected 4-membered rings
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
C : Chains of doubly-connected 4-membered rings
77.1.3.2
77 : TECTOSILICATES Zeolites
1 : Zeolite group - True zeolites
77 : TECTOSILICATES Zeolites
1 : Zeolite group - True zeolites
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Ami | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Amicite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
4½ on Mohs scale
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
2.06 - 2.23 g/cm3 (Measured) 2.16(2) g/cm3 (Calculated)
Optical Data of Amicite
Type:
Biaxial (-)
RI values:
nα = 1.485 nβ = 1.490 nγ = 1.494
2V:
Measured: 82°
Max. Birefringence:
δ = 0.009
Based on recorded range of RI values above.
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.
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.
Surface Relief:
Moderate
Dispersion:
very weak
Chemistry of Amicite
Mindat Formula:
K2Na2Al4Si4O16 · 5H2O
Element Weights:
Common Impurities:
Fe,Mg,Ca,Sr,Ba
Crystallography of Amicite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Cell Parameters:
a = 10.22 Å, b = 10.42 Å, c = 9.88 Å
β = 88.32°
β = 88.32°
Ratio:
a:b:c = 0.981 : 1 : 0.948
Unit Cell V:
1,051.69 ų (Calculated from Unit Cell)
Z:
2
Morphology:
As well-formed pseudotetragonal pyramidal crystals, to 5 mm, showing {011} and {110}, or more rarely {111} and {110}.
Comment:
Space Group: I2
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0009695 | Amicite | Alberti A, Vezzalini G (1979) The crystal structure of amicite, a zeolite Acta Crystallographica B35 2866-2869 |  | 1979 | basaltic rock at Howenegg in Hegau, southern West Germany | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.722 Å | (100) |
| 4.220 Å | (90) |
| 3.141 Å | (80) |
| 7.295 Å | (55) |
| 2.704 Å | (50) |
| 3.238 Å | (45) |
| 5.108 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Geological Setting:
in natrolite veinlets cutting ijolite-urtite pegmatites and apatite-nepheline rocks (Kola Peninsula, Russia).
Type Occurrence of Amicite
General Appearance of Type Material:
well-formed pseudotetragonal pyramidal crystals, to 5 mm
Place of Conservation of Type Material:
University of Modena, Modena, Italy; The Natural History Museum, London, England; National Museum of Natural History, Washington, D.C., USA, 145843.
Geological Setting of Type Material:
In veinlets cutting melilite-nephelinite volcanic rocks and pyroclastics
Associated Minerals at Type Locality:
Synonyms of Amicite
Other Language Names for Amicite
Relationship of Amicite to other Species
Member of:
Other Members of Zeolite Group:
| Alflarsenite | NaCa2Be3Si4O13(OH) · 2H2O | Mon. 2 : P21 |
| Ammonioleucite | (NH4)(AlSi2O6) | Tet. 4/m : I41/a |
| Analcime | Na(AlSi2O6) · H2O | Tric. 1 : P1 |
| Arzamastsevite | K6Al5Si6O20(OH)4Cl | Tet. 4 2m : I4 2m |
| Bellbergite | (K,Ba,Sr)2Sr2Ca2(Ca,Na)4[Al3Si3O12]6 · 30H2O | Hex. |
| Bikitaite | LiAlSi2O6 · H2O | Tric. 1 : P1 |
| Boggsite | Ca8Na3(Si,Al)96O192 · 70H2O | Orth. mmm (2/m 2/m 2/m) : Imma |
| Brewsterite Subgroup | Zeolite Group. | |
| Chabazite-Levyne Subgroup | M[Al2Si4O12] · 6H2O | |
| Chiavennite | CaMnBe2Si5O13(OH)2 · 2H2O | Mon. 2/m : P21/b |
| Clinoptilolite Subgroup | (Na/Ca/K)3-6[Al6-7Si29-30O72] · 20H2O | |
| Cowlesite | CaAl2Si3O10 · 6H2O | Orth. mmm (2/m 2/m 2/m) |
| Dachiardite Subgroup | Zeolite Group. | |
| Direnzoite | NaK6MgCa2(Al13Si47O120) · 36H2O | Orth. mmm (2/m 2/m 2/m) : Pmmn |
| Edingtonite | Ba[Al2Si3O10] · 4H2O | Orth. 2 2 2 : P21 21 21 |
| Epistilbite | CaAl2Si6O16 · 5H2O | Mon. |
| Erionite Subgroup | M2[Al4Si14O36] · 15H2O | |
| Fabrièsite | Na3Al3Si3O12 · 2H2O | Orth. mm2 : Pmm2 |
| Faujasite Subgroup | M3.5[Al7Si17O48] · 32H2O | |
| Ferrierite Subgroup | Zeolite Group. | |
| Ferrochiavennite | Ca1-2Fe[(Si,Al,Be)5Be2O13(OH)2] · 2H2O | Mon. 2/m : P21/b |
| Flörkeite | (K3Ca2Na)[Al8Si8O32] · 12H2O | Tric. 1 : P1 |
| Garronite Subgroup | ||
| Gaultite | Na4Zn2Si7O18 · 5H2O | Orth. mm2 : Fdd2 |
| Gismondine Subgroup | Zeolite Group. | |
| Gmelinite Subgroup | In 1997, gmelinite was split into Gmelinite-Ca, Gmelinite-Na and Gmelinite-K. | |
| Gobbinsite | Na5(Si11Al5)O32 · 11H2O | Orth. mmm (2/m 2/m 2/m) : Pnma |
| Goosecreekite | Ca[Al2Si6O16] · 5H2O | Mon. 2 : P21 |
| Gottardiite | Na3Mg3Ca5Al19Si117O272 · 93H2O | Orth. mmm (2/m 2/m 2/m) : Cmca |
| Heulandite Subgroup | (Na/Ca/K)5-6[Al8-9 Si27-28 O72] · nH2O | |
| Hsianghualite | Ca3Li2(Be3Si3O12)F2 | Iso. 4 3 2 : I41 3 2 |
| Kalborsite | K6Al4BSi6O20(OH)4Cl | Tet. 4 2m : P4 21c |
| Kirchhoffite | Cs(BSi2O6) | Tet. 4/mmm (4/m 2/m 2/m) : I41/acd |
| Laumontite | CaAl2Si4O12 · 4H2O | Mon. 2/m : B2/m |
| Leucite | K(AlSi2O6) | Tet. 4/m : I41/a |
| Limousinite | BaCa[Be4P4O16] · 6H2O | Mon. 2/m : P21/b |
| Lithosite | K6Al4Si8O25 · 2H2O | Mon. |
| Loomisite | Ba[Be2P2O8] · H2O | Mon. m |
| Lovdarite | K2Na6Be4Si14O36 · 9H2O | Orth. mm2 |
| Maricopaite | Pb7Ca2(Si,Al)48O100 · 32H2O | Orth. |
| Martinandresite | Ba2(Al4Si12O32) · 10H2O | Orth. mmm (2/m 2/m 2/m) : Pmmn |
| Mazzite Subgroup | Zeolite Group. | |
| Meierite | Ba44Si66Al30O192Cl25(OH)33 | Iso. m3m (4/m 3 2/m) : Im3m |
| Merlinoite | K5Ca2(Si23Al9)O64 · 24H2O | Orth. mmm (2/m 2/m 2/m) : Immm |
| Montesommaite | (K,Na)9Al9Si23O64 · 10H2O | Orth. mm2 : Fdd2 |
| Mordenite | (Na2,Ca,K2)4(Al8Si40)O96 · 28H2O | Orth. |
| Mountainite | KNa2Ca2[Si8O19(OH)] · 6H2O | Mon. 2/m : P2/b |
| Mutinaite | Na3Ca4Si85Al11O192 · 60H2O | Orth. mmm (2/m 2/m 2/m) : Pnma |
| Nabesite | Na2BeSi4O10 · 4H2O | Orth. 2 2 2 : P21 21 21 |
| Natrolite Subgroup | A subgroup of the Zeolite Group. | |
| Offretite | KCaMg(Si13Al5)O36 · 15H2O | Hex. 6 m2 : P6m2 |
| Pahasapaite | Li8(Ca,Li,K)10.5Be24(PO4)24 · 38H2O | Iso. 2 3 : I2 3 |
| Parthéite | Ca2(Si4Al4) O15 (OH)2 · 4H2O | Mon. 2/m : B2/b |
| Paulingite Subgroup | Paulingite was originally described in 1960. | |
| Perlialite | K9Na(Ca,Sr)[Al2Si4O12]6 · 15H2O | Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm |
| Phillipsite Subgroup | (Ca0.5,K,Na,Ba0.5)4-7[Al4-7Si12-9O32] . 12H2O | |
| Pollucite | (Cs,Na)2(Al2Si4O12) · 2H2O | Iso. m3m (4/m 3 2/m) : Ia3d |
| Roggianite | Ca2Be(OH)2Al2Si4O13 · 2.5H2O | Tet. 4/mmm (4/m 2/m 2/m) : I4/mcm |
| Rongibbsite | Pb2(Si4Al)O11(OH) | Mon. 2/m : B2/m |
| Stilbite Subgroup | M6-7[Al8-9Si27-28O72] · nH2O | |
| Terranovaite | (Na,Ca)8(Si68Al12)O160 · 29H2O | Orth. |
| Thomsonite Subgroup | The large majority of "thomsonite" is thomsonite-Ca. | |
| Thornasite | (Na,K)12Th3[Si8O19]4 · 18H2O | Trig. 3m : R3m |
| Tschernichite | (Ca,Na2)[Al2Si4O12] · 4-8H2O | Tet. 4/mmm (4/m 2/m 2/m) : P4/mmm |
| Tschörtnerite | Ca4(Ca,Sr,K,Ba)3Cu3[Al3Si3O12]4(OH)8 · nH2O | Iso. m3m (4/m 3 2/m) : Fm3m |
| UM1996-38-SiO:AlCaHNa | Na-Ca-Al-Si-O-H | |
| UM1999-33-SiO:AlHKNa | K7Na5Al12Si20O64 · 24H2O | |
| UM2002-40-SiO:AlCaHKMgNa | (Mg,Ca,Na,K)7.5(Al12.8Si51.2)O128 · 65H2O | Tet. 4 2 2 : P41 2 2 |
| Unnamed (Ca analogue of Merlinoite) | (Ca,K,Na)5(Ca,Ba)2Al9Si23O64 · 23H2O ? | |
| Wairakite | Ca(Al2Si4O12) · 2H2O | Mon. 2/m : B2/m |
| Weinebeneite | CaBe3(PO4)2(OH)2 · 4H2O | Mon. m : Bb |
| Wenkite | (Ba,K)4(Ca,Na)6[(Si,Al)20O39(OH)2](SO4)3 · 0.5H2O | Hex. 6 m2 : P62m |
| Wilancookite | (Ba5Li2◻)Ba6Be24P24O96 · 26H2O | Iso. 2 3 : I2 3 |
| Willhendersonite | KCa[Al3Si3O12] · 5H2O | Tric. 1 : P1 |
| Yugawaralite | CaAl2Si6O16 · 4H2O | Mon. m : Pb |
Common Associates
Associated Minerals Based on Photo Data:
| 4 photos of Amicite associated with Natrolite | Na2Al2Si3O10 · 2H2O |
| 1 photo of Amicite associated with Sitinakite | KNa2Ti4(SiO4)2O5(OH) · 4H2O |
| 1 photo of Amicite associated with Merlinoite | K5Ca2(Si23Al9)O64 · 24H2O |
| 1 photo of Amicite associated with Goethite | Fe3+O(OH) |
Related Minerals - Strunz-mindat Grouping
| 9.GC. | Gismondine-Sr | Sr4(Si8Al8O32) · 9H2O |
| 9.GC. | Garronite-Na | Na6(Al6Si10O32) · 8.5H2O |
| 9.GC.05 | Gismondine-Ba | Ba2Al4Si4O16 · 4-6H2O |
| 9.GC.05 | Garronite-Ca | Na2Ca5Al12Si20O64 · 27H2O |
| 9.GC.05 | Gismondine-Ca | CaAl2Si2O8 · 4H2O |
| 9.GC.05 | Gobbinsite | Na5(Si11Al5)O32 · 11H2O |
| 9.GC.10 | Martinandresite | Ba2(Al4Si12O32) · 10H2O |
| 9.GC.10 | Harmotome | Ba2(Si12Al4)O32 · 12H2O |
| 9.GC.10 | Phillipsite-Ca | Ca3(Si10Al6)O32 · 12H2O |
| 9.GC.10 | Phillipsite-K | K6(Si10Al6)O32 · 12H2O |
| 9.GC.10 | Phillipsite-Na | (Na,K,Ca0.5,Ba0.5)4-7[Al4-7Si12-9O32] · 12H2O |
| 9.GC.10 | Flörkeite | (K3Ca2Na)[Al8Si8O32] · 12H2O |
| 9.GC.15 | Merlinoite | K5Ca2(Si23Al9)O64 · 24H2O |
| 9.GC.20 | Mazzite-Na | Na8[Al4Si14O36]2 · 30H2O |
| 9.GC.20 | Mazzite-Mg | (Mg,K,Ca)5(Si26Al10)O72 · 28H2O |
| 9.GC.25 | Perlialite | K9Na(Ca,Sr)[Al2Si4O12]6 · 15H2O |
| 9.GC.30 | Boggsite | Ca8Na3(Si,Al)96O192 · 70H2O |
| 9.GC.35 | Paulingite-Ca | (Ca,K,Na,Ba, ◻)10 (Si, Al)42O84 · 34H2O |
| 9.GC.35 | Paulingite-K | (K2,Ca,Na2,Ba)5[Al10Si35O90] · 45H2O |
| 9.GC.35 | Paulingite-Na | (Na2,K2,Ca,Ba)5[Al10Si35O90] · 45H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 11.3245% | 3,511 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Other Information
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 Amicite
mindat.org URL:
https://www.mindat.org/min-199.html
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References for Amicite
Reference List:
Alberti, A., Vezzalini, G. (1979) The crystal structure of amicite, a zeolite. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 35 (12) 2866-2869 doi:10.1107/s0567740879010852
Localities for Amicite
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Germany (TL) | |
| Alberti et al. (1979) +1 other reference |
Iceland | |
| Jackson et al. (2019) |
Israel | |
| Skrzyńska et al. (2023) |
Russia | |
| Pekov et al. (2008) |
| [World of Stones 95:5-6 +1 other reference |
Spain | |
| Calvo et al. (2013) |
USA | |
| Zach Capel |
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Kirovskii apatite mine, Kukisvumchorr Mt, Khibiny Massif, Murmansk Oblast, Russia