Genthelvite
A valid IMA mineral species - grandfathered
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About Genthelvite
Formula:
Be3Zn4(SiO4)3S
Colour:
Colourless, white, yellow, green, pink to red, darkens to brown and black on weathering
Lustre:
Vitreous
Hardness:
6 - 6½
Specific Gravity:
3.44 - 3.70
Crystal System:
Isometric
Member of:
Name:
Named in 1944 by Jewel Jeannette Glass, Richard Henry Jahns, and Rollin Elbert Stevens for its relationship to helvine and for Fredrick Augustus Genth [May 17, 1820 Wächtersbach, Hesse-Cassel - February 2, 1893 Philadelphia, Pennsylvania, USA], professor of mineralogy at the University of Pennsylvania. Genth first described genthelvite in 1892 but did not recommend a name. Genth's description appears in Am. Jour. Sci., 44, 385 (1892). Glass et al. (1944) named the mineral after Genth in the reference listed on the genthelvite descriptive page - see Am. Min., 29, nos. 3 & 4, 163-191 (1944).
Unique Identifiers
Mindat ID:
1673
Long-form identifier:
mindat:1:1:1673:1
GUID
(UUID V4):
(UUID V4):
88ab23c1-0b85-43ad-92e2-096fc9a40440
IMA Classification of Genthelvite
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Genthelvite
9.FB.10
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
B : Tektosilicates with additional anions
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
B : Tektosilicates with additional anions
Dana 7th ed.:
76.2.4.3
76.2.4.3
76 : TECTOSILICATES Al-Si Framework
2 : Al-Si Framework Feldspathoids and related species
76 : TECTOSILICATES Al-Si Framework
2 : Al-Si Framework Feldspathoids and related species
17.9.3
17 : Silicates Containing other Anions
9 : Silicates with sulphide or sulphite
17 : Silicates Containing other Anions
9 : Silicates with sulphide or sulphite
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 |
---|---|---|
Ghv | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Ghv | The 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 Genthelvite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless, white, yellow, green, pink to red, darkens to brown and black on weathering
Hardness:
6 - 6½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Poor/Indistinct
on {111} and {111}
on {111} and {111}
Fracture:
Irregular/Uneven
Density:
3.44 - 3.70 g/cm3 (Measured) 3.70 g/cm3 (Calculated)
Optical Data of Genthelvite
Type:
Isotropic
RI values:
nα = 1.738 - 1.752
Birefringence:
Isotropic minerals have no birefringence
Surface Relief:
Moderate
Chemistry of Genthelvite
Mindat Formula:
Be3Zn4(SiO4)3S
Common Impurities:
Al,Fe,Mn,Cu
Chemical Analysis
Oxide wt%:
1 | |
---|---|
SiO2 | 34.16 % |
Al2O3 | 0.84 % |
FeO | 0.08 % |
ZnO | 46.12 % |
BeO (calc.) | 11.99 % |
CaO | 0.03 % |
MnO | 5.61 % |
S | 5.45 % |
O=S | -2.73 % |
Total: | 101.55 % |
Sample references:
ID | Locality | Reference | Notes |
---|---|---|---|
1 | SM6 unit, Motzfeldt Centre, Igaliku Complex, Kujalleq, Greenland | Electron microprobe, Be estimated by assuming stoichiometric ratios with other anions. Results: Close to the Zn end-member, with relatively small amounts of MnO. |
Crystallography of Genthelvite
Crystal System:
Isometric
Class (H-M):
4 3m - Hextetrahedral
Space Group:
P4 3n
Cell Parameters:
a = 8.12(2) Å
Unit Cell V:
535.39 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals commonly tetrahedral and tristetrahedra, up to 5 cm in diameter; also as large rounded grains to 25cm
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) |
---|---|---|---|---|---|---|---|
0000969 | Genthelvite | Hassan I, Grundy H D (1985) The crystal structures of helvite group minerals, (MnFeZn)8(Be6Si6O24)S2 American Mineralogist 70 186-192 | 1985 | 0 | 293 | ||
0000970 | Genthelvite | Hassan I, Grundy H D (1985) The crystal structures of helvite group minerals, (MnFeZn)8(Be6Si6O24)S2 American Mineralogist 70 186-192 | 1985 | 0 | 293 |
CIF Raw Data - click here to close
Epitaxial Relationships of Genthelvite
Epitaxial Minerals:
Danalite | Be3Fe2+4(SiO4)3S |
Epitaxy Comments:
Genthelvite on danalite cores from Cheyenne Canyon, Colorado (Zito and Hanson, 2017).
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
3.320 Å | (100) |
1.916 Å | (80) |
2.168 Å | (70) |
2.567 Å | (65) |
1.657 Å | (65) |
1.483 Å | (50) |
1.435 Å | (50) |
Comments:
From Mt. Ste. Hilaire
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Near-surface Processes | |
23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
Stage 4b: Highly evolved igneous rocks | >3.0 |
34 : Complex granite pegmatites | |
35 : Ultra-alkali and agpaitic igneous rocks | |
Stage 5: Initiation of plate tectonics | <3.5-2.5 |
40 : Regional metamorphism (greenschist, amphibolite, granulite facies) |
Geological Setting:
In miarolitic cavities in granitic pegmatites; accessory mineral in alkaline granites and syenites, greisens, and skarns.
Type Occurrence of Genthelvite
Place of Conservation of Type Material:
Pennsylvania State University, University Park, Pennsylvania; National Museum of Natural History, Washington, D.C., USA, #127180; The Natural History Museum, London, England, #1976,427
Geological Setting of Type Material:
Found in granite and syenite pegmatites
Other Language Names for Genthelvite
Relationship of Genthelvite to other Species
Member of:
Other Members of this group:
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
88 photos of Genthelvite associated with Quartz | SiO2 |
57 photos of Genthelvite associated with Aegirine | NaFe3+Si2O6 |
40 photos of Genthelvite associated with Calcite | CaCO3 |
36 photos of Genthelvite associated with Albite | Na(AlSi3O8) |
34 photos of Genthelvite associated with Helvine | Be3Mn2+4(SiO4)3S |
32 photos of Genthelvite associated with Microcline | K(AlSi3O8) |
31 photos of Genthelvite associated with Magnetite | Fe2+Fe3+2O4 |
25 photos of Genthelvite associated with Catapleiite | Na2Zr(Si3O9) · 2H2O |
21 photos of Genthelvite associated with Polylithionite | KLi2Al(Si4O10)(F,OH)2 |
20 photos of Genthelvite associated with Rhodochrosite | MnCO3 |
Related Minerals - Strunz-mindat Grouping
9.FB. | Steudelite | Na3(K17Ca7)Ca4(Al24Si24O96)(SO3)6F6 · 4H2O |
9.FB. | Sapozhnikovite | Na8(Al6Si6O24)(HS)2 |
9.FB. | Betzite | Na6Ca2(Al6Si6O24)Cl4 |
9.FB. | Slyudyankaite | Na28Ca4(Si24Al24O96)(SO4)6(S6)1/3(CO2) · 2H2O |
9.FB. | Bolotinaite | (Na7◻)(Al6Si6O24)F · 4H2O |
9.FB. | Wenlanzhangite-(Y) | Y2V3+2V4+2(SiO4)2O4(OH)4 |
9.FB.05 | Afghanite | (Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6 |
9.FB.05 | Bystrite | (Na,K)7Ca(Al6Si6O24)(S5)Cl |
9.FB.05 | Cancrinite | (Na,Ca,◻)8(Al6Si6O24)(CO3,SO4)2 · 2H2O |
9.FB.05 | Cancrisilite | Na7(Al5Si7O24)(CO3) · 3H2O |
9.FB.05 | Davyne | (Na,K)6Ca2(Al6Si6O24)(Cl2,SO4)2 |
9.FB.05 | Franzinite | (Na,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2O |
9.FB.05 | Giuseppettite | (Na,K,Ca)7-8(Al6Si6O24)(SO4,Cl)1-2 |
9.FB.05 | Hydroxycancrinite | Na8(Al6Si6O24)(OH)2 · 2H2O |
9.FB.05 | Liottite | (Na,K)16Ca8(Al6Si6O24)3(SO4)5Cl4 |
9.FB.05 | Microsommite | Na4K2Ca2(Al6Si6O24)(SO4)Cl2 |
9.FB.05 | Pitiglianoite | Na6K2(Al6Si6O24)(SO4) · 2H2O |
9.FB.05 | Quadridavyne | (Na,K)6Ca2(Al6Si6O24)Cl4 |
9.FB.05 | Sacrofanite | (Na61K19Ca32)(Si84Al84O336)(SO4)26Cl2F6 · 2H2O |
9.FB.05 | Tounkite | (Na,Ca,K)8(Al6Si6O24)(SO4)2Cl · H2O |
9.FB.05 | Vishnevite | (Na,K)8(Al6Si6O24)(SO4,CO3) · 2H2O |
9.FB.05 | Marinellite | (Na,K)42Ca6(Al6Si6O24)6(SO4)8Cl2 · 3H2O |
9.FB.05 | Farneseite | (Na,Ca,K)56(Al6Si6O24)7(SO4)12 · 6H2O |
9.FB.05 | Alloriite | (Na,Ca,K)26Ca4(Al6Si6O24)4(SO4)6Cl6 |
9.FB.05 | Biachellaite | (Na,Ca,K)8(Al6Si6O24)(SO4)2(OH)0.5 · H2O |
9.FB.05 | Fantappièite | [Na82.5Ca33K16.5](Si99Al99O396)(SO4)33 · 4H2O |
9.FB.05 | Kyanoxalite | Na7(Al6-xSi6+xO24)(C2O4)0.5+x · 5H2O (0 < x < 0.5) |
9.FB.05 | Balliranoite | (Na,K)6Ca2(Si6Al6O24)Cl2(CO3) |
9.FB.05 | Carbobystrite | Na8(Al6Si6O24)(CO3) · 3.5H2O |
9.FB.05 | Depmeierite | Na8(Al6Si6O24)(PO4,CO3)1-x · 3H2O (x |
9.FB.05 | Kircherite | Na5Ca2K(Al6Si6O24)(SO4)2 · 0.33H2O |
9.FB.05 | Sulfhydrylbystrite | Na5K2Ca[Al6Si6O24](S5)2(SH) |
9.FB.10 | Bicchulite | Ca2(Al2SiO6)(OH)2 |
9.FB.10 | Danalite | Be3Fe2+4(SiO4)3S |
9.FB.10 va | Hackmanite | Na8Al6Si6O24(Cl2,S) |
9.FB.10 | Haüyne | Na3Ca(Si3Al3)O12(SO4) |
9.FB.10 | Helvine | Be3Mn2+4(SiO4)3S |
9.FB.10 | Kamaishilite | Ca2(Al2SiO6)(OH)2 |
9.FB.10 | Lazurite | Na7Ca(Al6Si6O24)(SO4)(S3) · H2O |
9.FB.10 | Nosean | Na8(Al6Si6O24)(SO4) · H2O |
9.FB.10 | Sodalite | Na4(Si3Al3)O12Cl |
9.FB.10 | Tsaregorodtsevite | (N(CH3)4)(AlSi5O12) |
9.FB.10 | Tugtupite | Na4BeAlSi4O12Cl |
9.FB.10 | Vladimirivanovite | Na6Ca2(Al6Si6O24)(SO4,S3,S2,Cl)2 · H2O |
9.FB.15 | Marialite | Na4Al3Si9O24Cl |
9.FB.15 | Meionite | Ca4Al6Si6O24CO3 |
9.FB.15 | Silvialite | (Ca,Na)4(Al6Si6O24)(SO4,CO3) |
Fluorescence of Genthelvite
Strong green fluorescence in long- and short-wave ultraviolet; short-lived phosphorescence.
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 Genthelvite
mindat.org URL:
https://www.mindat.org/min-1673.html
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References for Genthelvite
Reference List:
Glass, Jewell J., Jahns, Richard H., Stevens, and Rollin E (1944) Helvite and danalite from New Mexico and the helvite group. American Mineralogist, 29 (5-6) 163-191
Glass, Jewell J., Adams, John W. (1953) Notes and news: Genthelvite crystal from El Paso County, Colorado. American Mineralogist, 38 (9-10) 858-859
Scott, Glenn R. (1957) Genthelvite from Cookstove Mountain, El Paso County, Colorado. American Mineralogist, 42 (5-6) 425-429
Finch, Adrian A. (1990) Genthelvite and willemite, zinc minerals associated with alkaline magmatism from the Motzfeldt centre, South Greenland. Mineralogical Magazine, 54 (376) 407-412 doi:10.1180/minmag.1990.054.376.05
Antao, S. M., Hassan, I. (2010) A two-phase intergrowth in genthelvite from Mont Saint-Hilaire, Quebec. The Canadian Mineralogist, 48 (5) 1217-1223 doi:10.3749/canmin.48.5.1217
Localities for Genthelvite
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).
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.
All localities listed without proper references should be considered as questionable.
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El Criollo Mine, Cerro Blanco pegmatite district, Tanti, San Roque District, Punilla Department, Córdoba Province, Argentina