Gmelinite-K
A valid IMA mineral species
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About Gmelinite-K
Christian Gottlob Gmelin
Formula:
K4(Si8Al4O24) · 11H2O
Colour:
Colorless to brownish
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.00
Crystal System:
Hexagonal
Member of:
Name:
Named after the German mineralogist and chemist, Christian Gottlob Gmelin (1792-1860) of Tübingen, Germany. The suffix indicates the dominant extra-framework cation. In 1997, the name gmelinite (without suffix) was promoted from species to series and gmelinite-K was defined as one of several species.
This page provides mineralogical data about Gmelinite-K.
Unique Identifiers
Mindat ID:
6972
Long-form identifier:
mindat:1:1:6972:0
Similar Names
| Gmelinite | A synonym of Gmelinite Subgroup | |
| Gmelinite-Ca | A valid IMA mineral species | Ca2(Si8Al4)O24 · 11H2O |
IMA Classification of Gmelinite-K
Approved
IMA Formula:
K4(Si8Al4)O24·11H2O
Approval year:
1999
Type description reference:
Coombs, Douglas S., Alberti, Alberto, Armbruster, Thomas, Artioli, Gilberto, Colella, Carmine, Galli, Ermanno, Grice, Joel D., Liebau, Friedrich, Mandarino, Joseph A., Minato, Hideo, et al. (1997) Recommended nomenclature for zeolite minerals; report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35 (6). 1571-1606
Classification of Gmelinite-K
9.GD.05
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
D : Chains of 6-membered rings – tabular zeolites
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
D : Chains of 6-membered rings – tabular zeolites
Mineral Symbols
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.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Gme-K | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Gme | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
Physical Properties of Gmelinite-K
Vitreous
Transparency:
Transparent
Colour:
Colorless to brownish
Streak:
White
Hardness:
4½ on Mohs scale
Hardness:
VHN30=258 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
2.00 g/cm3 (Measured) 2.04 g/cm3 (Calculated)
Optical Data of Gmelinite-K
Type:
Uniaxial (+/-)
RI values:
nα = 1.472 nβ = 1.477
Surface Relief:
Unknown
Pleochroism:
Non-pleochroic
Chemistry of Gmelinite-K
Mindat Formula:
K4(Si8Al4O24) · 11H2O
Element Weights:
Crystallography of Gmelinite-K
Crystal System:
Hexagonal
Class (H-M):
6/mmm(6/m2/m2/m) - Dihexagonal Dipyramidal
Space Group:
P63/mmc
Setting:
P63/mmc
Cell Parameters:
a = 13.621(3) Å, c = 10.254(1) Å
Ratio:
a:c = 1 : 0.753
Unit Cell V:
1,647.56 ų (Calculated from Unit Cell)
Z:
4
Morphology:
{100}, {101} and {001}.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0015872 | Gmelinite-K | Sacerdoti M, Passaglia E, Carnevali R (1995) Structural refinements of Na-, K-, and Ca-exchanged gmelinites Zeolites 15 276-281 | 1995 | Queensland, Australia | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.9 Å | (80) |
| 5.16 Å | (70) |
| 4.11 Å | (100) |
| 3.27 Å | (70) |
| 2.971 Å | (80) |
| 2.852 Å | (80) |
| 2.719 Å | (100) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 16 : Low-? aqueous alteration of Hadean subaerial lithologies (see also #23) | |
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Type Occurrence of Gmelinite-K
Co-Type Localities:
General Appearance of Type Material:
Granular and radial aggregates of columnar to acicular crystals up to 0.1 x 3 mm (Russia).
Geological Setting of Type Material:
Found in cavities within brecciated pegmatite (Russia).
Associated Minerals at Type Locality:
Reference:
Coombs, Douglas S., Alberti, Alberto, Armbruster, Thomas, Artioli, Gilberto, Colella, Carmine, Galli, Ermanno, Grice, Joel D., Liebau, Friedrich, Mandarino, Joseph A., Minato, Hideo, et al. (1997) Recommended nomenclature for zeolite minerals; report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35 (6). 1571-1606
Synonyms of Gmelinite-K
Other Language Names for Gmelinite-K
Relationship of Gmelinite-K to other Species
Member of:
Other Members of Gmelinite Subgroup:
| Gmelinite-Ca | Ca2(Si8Al4)O24 · 11H2O | Hex. 6/mmm(6/m2/m2/m) : P63/mmc |
| Gmelinite-Na | Na4(Si8Al4)O24 · 11H2O | Hex. 6/mmm(6/m2/m2/m) : P63/mmc |
Common Associates
Associations Based on Photo Data:
| 30 photos of Gmelinite-K associated with Analcime | Na(AlSi2O6) · H2O |
| 22 photos of Gmelinite-K associated with Chabazite-Ca | (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O |
| 6 photos of Gmelinite-K associated with Ussingite | Na2AlSi3O8OH |
| 6 photos of Gmelinite-K associated with Natrolite | Na2Al2Si3O10 · 2H2O |
| 6 photos of Gmelinite-K associated with Thomsonite-Ca | NaCa2[Al5Si5O20] · 6H2O |
| 3 photos of Gmelinite-K associated with Serandite | NaMn2+2Si3O8(OH) |
| 3 photos of Gmelinite-K associated with Vuonnemite | Na11Ti4+Nb2(Si2O7)2(PO4)2O3(F,OH) |
| 2 photos of Gmelinite-K associated with Umbozerite | Na3Sr4Th[Si(O,OH)3-4]8 |
| 2 photos of Gmelinite-K associated with Belovite-(Ce) | NaCeSr3(PO4)3F |
| 1 photo of Gmelinite-K associated with Neotocite | (Mn,Fe)SiO3 · H2O (?) |
Related Minerals - Strunz-mindat Grouping
| 9.GD.05 | Gmelinite-Ca | Ca2(Si8Al4)O24 · 11H2O |
| 9.GD.05 | Gmelinite-Na | Na4(Si8Al4)O24 · 11H2O |
| 9.GD.10 | Chabazite-Mg | (Mg0.7K0.5Ca0.5Na0.1)[Al3Si9O24] · 10H2O |
| 9.GD.10 | Willhendersonite | KCa[Al3Si3O12] · 5H2O |
| 9.GD.10 | Chabazite-Ca | (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O |
| 9.GD.10 | Chabazite-K | (K2,Ca,Na2,Sr,Mg)2[Al2Si4O12]2 · 12H2O |
| 9.GD.10 | Chabazite-Na | (Na2,K2,Ca,Sr,Mg)2[Al2Si4O12]2 · 12H2O |
| 9.GD.10 | Chabazite-Sr | Sr2[Al2Si4O12]2 · 12H2O |
| 9.GD.15 | Lévyne-Ca | (Ca,Na2,K2)[Al2Si4O12] · 6H2O |
| 9.GD.15 | Lévyne-Na | (Na2,Ca,K2)[Al2Si4O12] · 6H2O |
| 9.GD.20 | Erionite-Ca | (Ca,K2,Na2)2[Al4Si14O36] · 15H2O |
| 9.GD.20 | Erionite-K | (K2,Ca,Na2)2[Al4Si14O36] · 15H2O |
| 9.GD.20 | Erionite-Na | (Na2,K2,Ca)2[Al4Si14O36] · 15H2O |
| 9.GD.20 | Bellbergite | (K,Ba,Sr)2Sr2Ca2(Ca,Na)4[Al3Si3O12]6 · 30H2O |
| 9.GD.25 | Offretite | KCaMg(Si13Al5)O36 · 15H2O |
| 9.GD.25 | Wenkite | (Ba,K)4(Ca,Na)6[(Si,Al)20O39(OH)2](SO4)3 · 0.5H2O |
| 9.GD.30 | Faujasite-Ca | (Ca,Na2,Mg)3.5[Al7Si17O48] · 32H2O |
| 9.GD.30 | Faujasite-Mg | (Mg,Na2,Ca)3.5[Al7Si17O48] · 32H2O |
| 9.GD.30 | Faujasite-Na | (Na2,Ca,Mg)3.5[Al7Si17O48] · 32H2O |
| 9.GD.35 | Maricopaite | Pb7Ca2(Si,Al)48O100 · 32H2O |
| 9.GD.35 | Mordenite | (Na2,Ca,K2)4(Al8Si40)O96 · 28H2O |
| 9.GD.40 | Dachiardite-K | K4(Si20Al4O48) · 13H2O |
| 9.GD.40 | Dachiardite-Ca | (Ca,Na2,K2)5Al10Si38O96 · 25H2O |
| 9.GD.40 | Dachiardite-Na | (Na2,Ca,K2)5Al10Si38O96 · 25H2O |
| 9.GD.45 | Epistilbite | CaAl2Si6O16 · 5H2O |
| 9.GD.50 | Ferrierite-K | (K,Na)5(Si31Al5)O72 · 18H2O |
| 9.GD.50 | Ferrierite-Mg | [Mg2(K,Na)2Ca0.5](Si29Al7)O72 · 18H2O |
| 9.GD.50 | Ferrierite-Na | (Na,K)5(Si31Al5)O72 · 18H2O |
| 9.GD.50 | Ferrierite-NH4 | (NH4,Mg0.5)5(Al5Si31O72) · 22H2O |
| 9.GD.55 | Bikitaite | LiAlSi2O6 · H2O |
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) | 14.6004% | 4,526 | 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
Fluorescence of Gmelinite-K
Not fluorescent
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 Gmelinite-K
mindat.org URL:
https://www.mindat.org/min-6972.html
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References for Gmelinite-K
Reference List:
Sacerdoti, M., Passaglia, E., Carnevali, R. (1995) Structural refinements of Na-, K-, and Ca-exchanged gmelinites. Zeolites, 15 (3) 276-281 doi:10.1016/0144-2449(94)00024-m
Coombs, Douglas S., Alberti, Alberto, Armbruster, Thomas, Artioli, Gilberto, Colella, Carmine, Galli, Ermanno, Grice, Joel D., Liebau, Friedrich, Mandarino, Joseph A., Minato, Hideo, et al. (1997) Recommended nomenclature for zeolite minerals; report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35 (6). 1571-1606
Jambor, John L., Grew, Edward S., Roberts, Andrew C. (2002) New mineral names. American Mineralogist, 87. 1509-1513
Localities for Gmelinite-K
Showing 9 localities.
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.
Czech Republic | |
| Pauliš et al. (2021) |
Italy | |
| Vezzalini et al. (1990) +1 other reference |
| Boscardin et al. (2011) | |
| Rivista Mineralogica Italiana vol.17 fasc.2 1994 pp. 131-136 Studi e Ricerche-Associazione Amici del Museo - Museo Civico "G. Zannato" Montecchio Maggiore (VI) |
Russia (TL) | |
| Pekov (2000) +3 other references |
| Pavel M. Kartashov (n.d.) |
| Excalibur Mineral Corp. - Mineral News +1 other reference |
Spain | |
| Zeolite collection of Volker Betz |
| Collection of Volker Betz |
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Barranco de Carrizo, La Aldea de San Nicolás, Gran Canaria, Las Palmas Province, Canary Islands, Spain