Obertiite Root Name Group
A group of related mineral species
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About Obertiite Root Name Group
Roberta Oberti
Formula:
ANa2(Z2+3Z3+Ti)Si8O22O2
The obertiite minerals are WO2- dominant amphiboles defined with :
A(Na+K+2Ca)> 0.5 apfu,
X: Na dominant
ZTi > 0.5 apfu and
WO > 1.0 apfu
The positions X and Z refers to the IMA positions B and C respectively
The root-name mineral, obertiite is defined with Na, Mg, Al as the dominant elements in the A and Z positions (= IMA C position) respectively. Obertiite minerals with other dominant elements are named with pre-fixes in accordance with the guidelines established in the 2012 amphibole nomenclature.
On mindat.org we avoid using variables with the same symbol as elements and deviate from the IMA nomenclature in that we use X rather than B, Z rather than C and (OH,F,Cl,O) rather than W.
A(Na+K+2Ca)> 0.5 apfu,
X: Na dominant
ZTi > 0.5 apfu and
WO > 1.0 apfu
The positions X and Z refers to the IMA positions B and C respectively
The root-name mineral, obertiite is defined with Na, Mg, Al as the dominant elements in the A and Z positions (= IMA C position) respectively. Obertiite minerals with other dominant elements are named with pre-fixes in accordance with the guidelines established in the 2012 amphibole nomenclature.
On mindat.org we avoid using variables with the same symbol as elements and deviate from the IMA nomenclature in that we use X rather than B, Z rather than C and (OH,F,Cl,O) rather than W.
Member of:
Name:
The obertiite root name is for Prof. Roberta Oberti, University of Pavia, Italy, for her contributions to the crystal chemistry of amphiboles.
Naturally occurring obertiite minerals from the Eifel area show a variable composition in the mangani-obertiite/ ferri-obertiite/ferro-ferri-obertiite range and the following Fe:Mn ratio ranges have been determined by WDS/EDS analyses:
Bellerberg 8 samples of Fe:Mn between 4:1 and 3:2
Emmelberg 1 sample Fe:Mn = 3:1
Herchenberg 1 sample Fe:Mn = 4:1
Nickenicher Sattel 1 sample Fe:Mn = 3:1
Nick. Weinberg 1 sample Fe:Mn = 3:1
Wannenköpfe 1 sample Fe:Mn = 3:1
Rothenberg 6 samples Fe:Mn between 3:1 and 3:2 (1 sample 1.6:1.5)
In addition, one sample from Caspar quarry shows a Fe:Mn ratio of ~ 7:1 (EMPA data).
Data from Günter Blaß and Christof Schäfer (2014).
Bellerberg 8 samples of Fe:Mn between 4:1 and 3:2
Emmelberg 1 sample Fe:Mn = 3:1
Herchenberg 1 sample Fe:Mn = 4:1
Nickenicher Sattel 1 sample Fe:Mn = 3:1
Nick. Weinberg 1 sample Fe:Mn = 3:1
Wannenköpfe 1 sample Fe:Mn = 3:1
Rothenberg 6 samples Fe:Mn between 3:1 and 3:2 (1 sample 1.6:1.5)
In addition, one sample from Caspar quarry shows a Fe:Mn ratio of ~ 7:1 (EMPA data).
Data from Günter Blaß and Christof Schäfer (2014).
Unique Identifiers
Mindat ID:
46446
Long-form identifier:
mindat:1:1:46446:2
GUID
(UUID V4):
(UUID V4):
e2ac02fe-5912-4949-84cc-9808bc854543
Chemistry of Obertiite Root Name Group
Mindat Formula:
ANa2(Z2+3Z3+Ti)Si8O22O2
The obertiite minerals are WO2- dominant amphiboles defined with :
A(Na+K+2Ca)> 0.5 apfu,
X: Na dominant
ZTi > 0.5 apfu and
WO > 1.0 apfu
The positions X and Z refers to the IMA positions B and C respectively
The root-name mineral, obertiite is defined with Na, Mg, Al as the dominant elements in the A and Z positions (= IMA C position) respectively. Obertiite minerals with other dominant elements are named with pre-fixes in accordance with the guidelines established in the 2012 amphibole nomenclature.
On mindat.org we avoid using variables with the same symbol as elements and deviate from the IMA nomenclature in that we use X rather than B, Z rather than C and (OH,F,Cl,O) rather than W.
The obertiite minerals are WO2- dominant amphiboles defined with :
A(Na+K+2Ca)> 0.5 apfu,
X: Na dominant
ZTi > 0.5 apfu and
WO > 1.0 apfu
The positions X and Z refers to the IMA positions B and C respectively
The root-name mineral, obertiite is defined with Na, Mg, Al as the dominant elements in the A and Z positions (= IMA C position) respectively. Obertiite minerals with other dominant elements are named with pre-fixes in accordance with the guidelines established in the 2012 amphibole nomenclature.
On mindat.org we avoid using variables with the same symbol as elements and deviate from the IMA nomenclature in that we use X rather than B, Z rather than C and (OH,F,Cl,O) rather than W.
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) |
|---|---|---|---|---|---|---|---|
| 0002347 | Mangani-obertiite | Hawthorne F C, Cooper M A, Grice J D, Ottolini L (2000) A new anhydrous amphibole from the Eifel region, Germany: Description and crystal structure of obertiite, NaNa2(Mg3FeTi)Si8O22O2 American Mineralogist 85 236-241 |  | 2000 | Eifel region, Germany | 0 | 293 |
| 0002347 | Ferri-obertiite | Hawthorne F C, Cooper M A, Grice J D, Ottolini L (2000) A new anhydrous amphibole from the Eifel region, Germany: Description and crystal structure of obertiite, NaNa2(Mg3FeTi)Si8O22O2 American Mineralogist 85 236-241 | | 2000 | Eifel region, Germany | 0 | 293 |
CIF Raw Data - click here to close
Synonyms of Obertiite Root Name Group
Sodic amphibole (in part)
Relationship of Obertiite Root Name Group to other Species
Member of:
Other Members of this group:
| Kaersutite Root Name Group | ACa2(Z2+3Z3+Ti)(Si6Al2O22)O2 | Mon. |
| Mangani-dellaventuraite | NaNa2(MgMn3+2Ti4+Li)Si8O22O2 | Mon. 2/m : B2/m |
| Mangano-mangani-ungarettiite | NaNa2(Mn2+2Mn3+3)(Si8O22)O2 | Mon. 2/m : B2/m |
| Oxo-magnesio-hastingsite | NaCa2(Mg3(Fe3+2-x,Tix))5(Si6Al2O22)O2 | Mon. 2/m : B2/m |
| Oxo-pargasite | NaCa2(Mg3(Al2-x,Tix))5(Si6Al2O22)O2 | |
| Potassic-jeanlouisite | K(NaCa)(Mg4Ti)Si8O22O2 | Mon. 2/m : B2/m |
| Potassic-mangano-mangani-ungarettiite | KNa2(Mn2+2Mn3+3)Si8O22O2 |
Group Members:
| Ferri-obertiite | NaNa2(Mg3Fe3+Ti)Si8O22O2 | Mon. 2/m : B2/m |
| Ferro-ferri-obertiite | NaNa2(Fe2+3Fe3+Ti)Si8O22O2 | Mon. 2/m : B2/m |
| Mangani-obertiite | NaNa2(Mg3Mn3+Ti4+)Si8O22O2 | Mon. 2/m : B2/m |
| Unnamed (Possible K-analogue of Ferri-obertiite) | KNa2((Mg,Fe,Na)3Fe3+(Ti,Fe))Si8O22(O,F)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 Obertiite Root Name Group
mindat.org URL:
https://www.mindat.org/min-46446.html
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References for Obertiite Root Name Group
Reference List:
Oberti, Roberta, Ungaretti, Luciano, Cannillo, Elio, Hawthorne, Frank C. (1992) The behaviour of Ti in amphiboles: I. Four- and six-coordinate Ti in richterite. European Journal of Mineralogy, 4 (3) 425-440 doi:10.1127/ejm/4/3/0425
Hawthorne, Frank C., Cooper, Mark A., Grice, Joel D., Ottolini, Luisa (2000) A new anhydrous amphibole from the Eifel region, Germany: Description and crystal structure of obertiite, NaNa2(Mg3Fe3+Ti4+)Si8O22O2. American Mineralogist, 85 (1) 236-241 doi:10.2138/am-2000-0124
Hawthorne, F. C., Ball, N. A., Czamanske, G. K. (2010) Ferro-obertiite, NaNa2(Fe2+3Fe3+Ti)Si8O22O2, a new mineral species of the amphibole group from Coyote Peak, Humboldt County, California. The Canadian Mineralogist, 48 (2) 301-306 doi:10.3749/canmin.48.2.301
Localities for Obertiite Root Name Group
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 | |
| Blass |
| Williams et al. (2014) |
| [Ferri-obertiite] Mineralogical Magazine: 79: 1859–1864 +2 other references |
| Blass +2 other references |
| Hand Egon Künzel et al. (2011) | |
| [Mangani-obertiite] Hawthorne et al. (2000) |
| Graf +1 other reference |
Russia | |
| [Ferri-obertiite] Sharygin (2020) |
USA | |
| [Ferro-ferri-obertiite] Hawthorne et al. (2010) |
Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany