Hellandite Group
A group of related mineral species
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About Hellandite Group
Amund T. Helland
Formula:
X4Y2ZT2[B4Si4O22]W2
X = Na, Ca, Y, LREE3+ at the eightfold-coordinated M3 and M4 sites;
Y = Ca, Y, HREE3+, Th4+, U4+ at the eightfold-coordinated M2 site.
Z = Al, Mn3+, Fe3+, Ti4+ at the octahedral; M1 site T = □, Li, Be at the new tetrahedrally coordinated site
and W = OH, F, O2– at the O5 site (Oberti et al. 2002).
Y = Ca, Y, HREE3+, Th4+, U4+ at the eightfold-coordinated M2 site.
Z = Al, Mn3+, Fe3+, Ti4+ at the octahedral; M1 site T = □, Li, Be at the new tetrahedrally coordinated site
and W = OH, F, O2– at the O5 site (Oberti et al. 2002).
Name:
Amund Theodor Helland [October 11, 1846 Bergen, Norway - November 15, 1918 Oslo "Kristiania", Norway], was professor of geology and geography at the Royal Frederick University (University of Oslo).
Unique Identifiers
Mindat ID:
29214
Long-form identifier:
mindat:1:1:29214:8
Similar Names
| Heulandite Group | A synonym of Heulandite Subgroup |
| Hollandite Group | A synonym of Coronadite Group |
IMA Classification of Hellandite Group
IMA status notes:
IMA Approved Group Name, Redefined by the IMA
Approval history:
The hellandite group was redefined by IMA in 2000 (code 00-F).
Chemistry of Hellandite Group
Mindat Formula:
X4Y2ZT2[B4Si4O22]W2
X = Na, Ca, Y, LREE3+ at the eightfold-coordinated M3 and M4 sites;
Y = Ca, Y, HREE3+, Th4+, U4+ at the eightfold-coordinated M2 site.
Z = Al, Mn3+, Fe3+, Ti4+ at the octahedral; M1 site T = □, Li, Be at the new tetrahedrally coordinated site
and W = OH, F, O2– at the O5 site (Oberti et al. 2002).
X = Na, Ca, Y, LREE3+ at the eightfold-coordinated M3 and M4 sites;
Y = Ca, Y, HREE3+, Th4+, U4+ at the eightfold-coordinated M2 site.
Z = Al, Mn3+, Fe3+, Ti4+ at the octahedral; M1 site T = □, Li, Be at the new tetrahedrally coordinated site
and W = OH, F, O2– at the O5 site (Oberti et al. 2002).
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| CaO | 7.65 % |
| MnO | 7.71 % |
| Y2O3 | 31.60 % |
| La2O3 | 0.04 % |
| Ce2O3 | 0.29 % |
| Nd2O3 | 0.37 % |
| Sm2O3 | 0.25 % |
| Gd2O3 | 0.19 % |
| Dy2O3 | 0.90 % |
| Er2O3 | 0.93 % |
| Yb2O3 | 2.99 % |
| Al2O3 | 4.85 % |
| Fe2O3 | 0.62 % |
| SiO2 | 24.35 % |
| B2O3 | 15.32 % |
| ThO2 | 0.09 % |
| H20 (calc) | 1.83 % |
| Total: | 99.98 % |
Empirical formulas:
| Sample ID | Empirical Formula |
|---|---|
| 1 | Ca1.34Mn1.07Y2.75Ce0.02Nd0.02Sm0.01Gd0.01Dy0.05Er0.05Yb0.15Al0.94Fe0.08Si3.99B4.33O22.00(OH)2.00 |
| 2 | X(Ca)Y4(Ca0.40REE0.93(Th,U)4+0.54◻0.13)Σ2.00 Z(Fe3+0.50Al0.23Mn3+0.17Ti4+0.17)TΣ1.07(Be1.04Li0.04◻0.92)Σ2.00[Si4.03B3.89O22] (O1.09(OH)0.38F0.53)Σ2.00 |
Sample references:
| ID | Type | Locality | Reference | Notes |
|---|---|---|---|---|
| 1 | Heftetjern pegmatite, Tørdal, Drangedal, Telemark, Norway | Empirical formula calculted on the basis of Al + Fe + Si = 5 and 24 anions per formula unit. Chemical analysis : EDS mean of 6 analyzed spots. | ||
| 2 | Type Specimen | Vico volcanic complex, Viterbo Province, Lazio, Italy | The empirical formula derived from electron microprobe and LA-ICP-MS analyses |
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) |
|---|---|---|---|---|---|---|---|
| 0020232 | Hellandite-(Y) | Miyawaki R, Momma K, Yokoyama K, Shigeoka M, Matsubara S, Ito M, Nakai I, Kristiansen R (2015) Mn-bearing hellandite-(Y) from the Heftetjern pegmatite, Tordal, Norway The Canadian Mineralogist 53 345-356 | 2015 | Heftetjern, Tordal, Telemark, Norway | 0 | 293 | |
| 0005547 | Tadzhikite-(Ce) | Hawthorne F C, Cooper M A, Taylor M C (1998) Refinement of the crystal structure of tadzhikite The Canadian Mineralogist 36 817-822 |  | 1998 | Dara-i-Pioz, Tadzhikistan | 0 | 293 |
| 0002819 | Ciprianiite | Della Ventura G, Bonazzi P, Oberti R, Ottolini L (2002) Ciprianiite and mottanaite-(Ce), two new minerals of the hellandite group from Latium (Italy) American Mineralogist 87 739-744 | | 2002 | 0 | 293 | |
| 0002818 | Mottanaite-(Ce) | Della Ventura G, Bonazzi P, Oberti R, Ottolini L (2002) Ciprianiite and mottanaite-(Ce), two new minerals of the hellandite group from Latium (Italy) American Mineralogist 87 739-744 | | 2002 | 0 | 293 | |
| 0002237 | Hellandite-(Ce) | Oberti R, Ottolini L, Camara F, Della Ventura G (1999) Crystal structure of non-metamict Th-rich hellandite-(Ce) from Latium (Italy) and crystal chemistry of the hellandite-group minerals American Mineralogist 84 913-921 | | 1999 | 0 | 293 | |
| 0015611 | Tadzhikite-(Ce) | Chernitsova N M, Pudovkina Z V, Pyatenko Y A (1982) About the crystal structure of tadzhikite {(Ca,Tr)4(Y,Tr)2(Ti,Fe,Al)(O,OH)2 [Si4B4O22]} Soviet Physics Doklady 27 367-368 | 1982 | 0 | 293 | ||
| 0000557 | Hellandite-(Y) | Mellini M, Merlino S (1977) Hellandite: a new type of silicoborate chain American Mineralogist 62 89-99 | | 1977 | 0 | 293 |
CIF Raw Data - click here to close
Relationship of Hellandite Group to other Species
Hellandite Group Members:
| Ciprianiite | Ca4[(Th,U),Ca]Σ2Al(Be0.5◻1.5)Σ2[B4Si4O22](OH)2 | Mon. 2/m : P2/b |
| Ferri-hellandite-(Ce) | (Ca3Ce)Ce2Fe3+◻2B4Si4O22(OH)2 | Mon. 2/m : P2/b |
| Ferri-mottanaite-(Ce) | Ca4Ce2Fe3+(Be1.5◻0.5)[Si4B4O22]O2 | Mon. 2/m : P2/b |
| Hellandite-(Ce) | (Ca,REE)4Ce2Al◻2(B4Si4O22) (OH)2 | Mon. 2/m |
| Hellandite-(Y) | (Ca,REE)4Y2Al◻2(B4Si4O22) (OH)2 | Mon. 2/m : P2/b |
| Mottanaite-(Ce) | Ca4(Ce,REE)Σ2Al(Be1.5◻0.5)Σ2[B4Si4O22]O2 | Mon. 2/m |
| Tadzhikite-(Ce) | Ca4Ce3+2Ti◻2(B4Si4O22)(OH)2 | Mon. 2/m : P2/b |
Click on any node to view relationships. Formula-derived relationship network for the group members above. Use Find related species to add formula-neighbour species outside the current group view. Solid links show inferred chemical differences; dashed violet links show same-formula crystallographic differences. Hydration states are not treated as relationship changes. These relationships do not imply any real-world substitution reactions between these species.
Minerals structurally related to group:
| 'Hellandite-(Ce)' | (Ca,REE)4Ce2Al◻2(B4Si4O22) (OH)2 | |
| 'Hellandite-(Y)' | (Ca,REE)4Y2Al◻2(B4Si4O22) (OH)2 |
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 Hellandite Group
mindat.org URL:
https://www.mindat.org/min-29214.html
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References for Hellandite Group
Reference List:
Oberti, Roberta, Ottolini, Luisa, Camara, Fernando, Della Ventura, Giancarlo (1999) Crystal structure of non-metamict Th-rich hellandite-(Ce) from Latium (Italy) and crystal chemistry of the hellandite-group minerals. American Mineralogist, 84 (5) 913-921 doi:10.2138/am-1999-5-626
Oberti, Roberta, Ventura, Giancarlo Della, Ottolini, Luisa, Hawthorne, Frank C., Bonazzi, Paola (2002) Re-definition, nomenclature and crystal-chemistry of the hellandite group. American Mineralogist, 87 (5) 745-752 doi:10.2138/am-2002-5-618
Oberti, Roberta, Langone, Antonio, Boiocchi, Massimo, Bernabè, Ezio, Hawthorne, Frank C. (2019) News from the hellandite group: the redefinition of mottanaite and ciprianiite and the new mineral description of ferri-mottanaite-(Ce), the first Fe3+-dominant hellandite. European Journal of Mineralogy, 31 (4) 799-806 doi:10.1127/ejm/2019/0031-2858
Perna, Maria; Zaccaria, Daria; Rosatelli, Gianluigi; Stoppani, Francesco; Curti, Ezio; Spratt, John; Humphreys-Williams, Emma; Najorka, Jens; Brownscombe, Will; Nestola, Fabrizio; et al. (2021) Dissolution-Repackaging of Hellandite-(Ce), Mottanaite-(Ce)/Ferri-Mottanaite-(Ce). Minerals, 11 (6). 610 doi:10.3390/min11060610
Localities for Hellandite Group
Showing 68 localities.
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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.
Lindvikskollen Quarry, Lindvikskollen-Kalstadgangen pegmatite, Kragerø, Telemark, Norway