Osumilite-(Mg)
A valid IMA mineral species
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About Osumilite-(Mg)
Formula:
K◻2Mg2Al3[Al2Si10O30]
Colour:
Brown, blue
Lustre:
Vitreous
Hardness:
5 - 6½
Specific Gravity:
2.59
Crystal System:
Hexagonal
Member of:
Name:
For being the magnesium analogue of osumilite.
The Mg analogue of Osumilite.
Mg-dominant (at the octahedral site) analogues of osumilite have been described several times (Armbruster and Oberhänsli, 1988; Balassone et al., 2008; Seryotkin et al., 2008), but published without approval by the CNMNC.
The mineral was finally approved as a valid species by the IMA in 2011, based upon a complete investigation of a type specimen from Bellerberg, Eifel, Rheinland-Pfalz, Germany (Chukanov et al., 2013).
Note: All localities listed here should be checked if they are to be assigned under osumilite-(Mg) or osumilite.
Mg-dominant (at the octahedral site) analogues of osumilite have been described several times (Armbruster and Oberhänsli, 1988; Balassone et al., 2008; Seryotkin et al., 2008), but published without approval by the CNMNC.
The mineral was finally approved as a valid species by the IMA in 2011, based upon a complete investigation of a type specimen from Bellerberg, Eifel, Rheinland-Pfalz, Germany (Chukanov et al., 2013).
Note: All localities listed here should be checked if they are to be assigned under osumilite-(Mg) or osumilite.
Unique Identifiers
Mindat ID:
3038
Long-form identifier:
mindat:1:1:3038:6
GUID
(UUID V4):
(UUID V4):
d617adaf-101a-4cb8-89e4-335d55c5bdca
IMA Classification of Osumilite-(Mg)
Classification of Osumilite-(Mg)
9.CM.05
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
16.24.16
16 : Silicates Containing Aluminum and other Metals
24 : Aluminosilicates of Fe, Mg, Ca and alkalis
16 : Silicates Containing Aluminum and other Metals
24 : Aluminosilicates of Fe, Mg, Ca and alkalis
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 |
|---|---|---|
| Osm-Mg | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Osm | 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 |
| Osm | 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 Osumilite-(Mg)
Vitreous
Transparency:
Transparent
Colour:
Brown, blue
Streak:
White
Hardness:
5 - 6½ on Mohs scale
Comment:
Type description gives 6.5.
Tenacity:
Brittle
Cleavage:
None Observed
Density:
2.59(1) g/cm3 (Measured) 2.592(1) g/cm3 (Calculated)
Optical Data of Osumilite-(Mg)
Type:
Uniaxial (+)
RI values:
nω = 1.541 nε = 1.543
Max Birefringence:
δ = 0.002
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Pleochroism:
Weak
Comments:
ε = colorless to ω = light blue.
Comments:
Type description gives: ω = 1.539, ε = 1.547.
Chemistry of Osumilite-(Mg)
Mindat Formula:
K◻2Mg2Al3[Al2Si10O30]
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| SiO2 | 60.37 % |
| Al2O3 | 22.95 % |
| TiO2 | 0.22 % |
| FeO (tot.) | 3.95 % |
| MnO | 0.13 % |
| MgO | 7.02 % |
| Na2O | 0.59 % |
| K2O | 4.14 % |
| Cr2O3 | tr. % |
| CaO | tr. % |
| BaO | tr. % |
| Total: | 99.37 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Roadcut Fv 503 Vikesdal, Vikeså, Bjerkreim, Rogaland, Norway | Analysed with electron microprobe |
Crystallography of Osumilite-(Mg)
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P6/mcc
Cell Parameters:
a = 10.0959(9) Å, c = 14.3282(2) Å
Ratio:
a:c = 1 : 1.419
Unit Cell V:
1,264.77 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Type material:
Common crystal faces are {100} and {001} with rare {101} and {110}.
Common crystal faces are {100} and {001} with rare {101} and {110}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.21 Å | (37) |
| 5.538 Å | (36) |
| 5.064 Å | (85) |
| 4.137 Å | (45) |
| 3.736 Å | (43) |
| 3.234 Å | (100) |
| 2.932 Å | (42) |
| 2.767 Å | (51) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4a: Earth’s earliest continental crust | >4.4-3.0 |
| 20 : Acidic volcanic rocks | |
| High-𝑇 alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations |
Type Occurrence of Osumilite-(Mg)
General Appearance of Type Material:
Blue to brown transparent vitreous short prismatic or thick tabular hexagonal crystals up to 0.5 × 1 mm in size.
Place of Conservation of Type Material:
Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4174/1.
Geological Setting of Type Material:
In cavities in basaltic volcanic glasses at their contact with thermally metamorphosed xenoliths of pelitic rocks.
Associated Minerals at Type Locality:
Synonyms of Osumilite-(Mg)
Other Language Names for Osumilite-(Mg)
Relationship of Osumilite-(Mg) to other Species
Member of:
Other Members of this group:
| Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm |
| Aluminosugilite | KNa2Al2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Armenite | Ba(H2O)2Ca2Al3[Al3Si9O30] | Orth. mmm (2/m 2/m 2/m) : Pnna |
| Berezanskite | K◻2Ti2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Brannockite | K◻2Sn2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Eifelite | KNa2(MgNa)Mg3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc |
| Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Oftedalite | K◻2(ScCa)Be3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Osumilite | K◻2Fe2+2Al3[Al2Si10O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Poudretteite | K◻2Na2B3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Roedderite | K(◻Na)Mg2Mg3[Si12O30] | Hex. 6 m2 : P62c |
| Shibkovite | K(◻K)Ca2Zn3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Sogdianite | K◻2Zr2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Sugilite | KNa2Fe3+2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| UM1990-73-SiO:KMnNaZn | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] | Hex. |
| Unnamed (Mn3+-dominant analog of Sugilite) | KNa2Mn3+2Li3[Si12O30] | |
| Yagiite | Na◻2Mg2Al3[Al2Si10O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
Common Associates
Associated Minerals Based on Photo Data:
| 14 photos of Osumilite-(Mg) associated with Mullite | Al4+2xSi2-2xO10-x |
| 10 photos of Osumilite-(Mg) associated with Hematite | Fe2O3 |
| 8 photos of Osumilite-(Mg) associated with Cordierite | (Mg,Fe)2Al3(AlSi5O18) |
| 4 photos of Osumilite-(Mg) associated with Tridymite | SiO2 |
| 3 photos of Osumilite-(Mg) associated with Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| 3 photos of Osumilite-(Mg) associated with Pseudobrookite | Fe2TiO5 |
| 2 photos of Osumilite-(Mg) associated with Phlogopite | KMg3(AlSi3O10)(OH)2 |
| 2 photos of Osumilite-(Mg) associated with Sanidine | K(AlSi3O8) |
| 1 photo of Osumilite-(Mg) associated with Topaz | Al2(SiO4)(F,OH)2 |
| 1 photo of Osumilite-(Mg) associated with Pumpellyite-(Mn2+) | Ca2Mn2+Al2(Si2O7)(SiO4)(OH)2 · H2O |
Related Minerals - Strunz-mindat Grouping
| 9.CM. | Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] |
| 9.CM.05 | Armenite | Ba(H2O)2Ca2Al3[Al3Si9O30] |
| 9.CM.05 | Brannockite | K◻2Sn2Li3[Si12O30] |
| 9.CM.05 | Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] |
| 9.CM.05 | Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] |
| 9.CM.05 | Eifelite | KNa2(MgNa)Mg3[Si12O30] |
| 9.CM.05 | Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] |
| 9.CM.05 | Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] |
| 9.CM.05 | Osumilite | K◻2Fe2+2Al3[Al2Si10O30] |
| 9.CM.05 | Poudretteite | K◻2Na2B3[Si12O30] |
| 9.CM.05 | Roedderite | K(◻Na)Mg2Mg3[Si12O30] |
| 9.CM.05 | Sogdianite | K◻2Zr2Li3[Si12O30] |
| 9.CM.05 | Sugilite | KNa2Fe3+2Li3[Si12O30] |
| 9.CM.05 | Yagiite | Na◻2Mg2Al3[Al2Si10O30] |
| 9.CM.05 | Berezanskite | K◻2Ti2Li3[Si12O30] |
| 9.CM.05 | Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] |
| 9.CM.05 | Shibkovite | K(◻K)Ca2Zn3[Si12O30] |
| 9.CM.05 | Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] |
| 9.CM.05 | Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] |
| 9.CM.05 | Oftedalite | K◻2(ScCa)Be3[Si12O30] |
| 9.CM.05 | Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] |
| 9.CM.05 | Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] |
| 9.CM.05 | UM1990-73-SiO:KMnNaZn | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] |
| 9.CM.05 | Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] |
| 9.CM.9.CM. | Aluminosugilite | KNa2Al2Li3[Si12O30] |
| 9.CM.10 | Faizievite | K2Na(Ca6Na)Ti4Li6[Si6O18]2[Si12O30]F2 |
Other Information
IR Spectrum:
Very similar to that of osumilite.
Main absorption bands (cm–1, s = strong, sh = shoulder):
1138s, 1000sh, 950s [stretching vibrations of (Si,Al)O4 tetrahedra], 770sh, 745, 717, 652, 541s (mixed vibrations of tetrahedral rings), 475, 440, 401s, 378s (combined modes with bending vibrations Si-O-Si and stretching vibrations of Mg octahedra).
For osumilite the wavenumber of the latter band is lower (367 cm–1) due to the predominance of Fe+2 over Mg in the octahedral site. The bands related to H-, B-, or C-bearing groups are absent in IR spectrum
Main absorption bands (cm–1, s = strong, sh = shoulder):
1138s, 1000sh, 950s [stretching vibrations of (Si,Al)O4 tetrahedra], 770sh, 745, 717, 652, 541s (mixed vibrations of tetrahedral rings), 475, 440, 401s, 378s (combined modes with bending vibrations Si-O-Si and stretching vibrations of Mg octahedra).
For osumilite the wavenumber of the latter band is lower (367 cm–1) due to the predominance of Fe+2 over Mg in the octahedral site. The bands related to H-, B-, or C-bearing groups are absent in IR spectrum
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 Osumilite-(Mg)
mindat.org URL:
https://www.mindat.org/min-3038.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Osumilite-(Mg)
Reference List:
Miyashiro, A (1953) Osumilite, a New Mineral, and Cordierite in Volcanic Rocks. Proceedings of the Japan Academy, 29 (7) 321-323 doi:10.2183/pjab1945.29.321
Miyashiro, Akiho (1956) Osumilite, a new silicate mineral and its crystal structure. American Mineralogist, 41 (1-2) 104-116
Brown, G. E., Gibbs, G. V. (1969) Refinement of the crystal structure of osumilite. American Mineralogist, 54 (1-2) 101-116
Olsen, Edward, Bunch, T. E. (1970) Compositions of natural osumilites. American Mineralogist, 55 (5-6) 875-879
Chinner, G. A., Dixon, P. D. (1973) Irish osumilite. Mineralogical Magazine, 39 (302) 189-192 doi:10.1180/minmag.1973.039.302.06
Berg, Jonathan H., Wheeler, E. P. (1976) Osumilite of deep-seated origin in the contact aureole of the anorthositic Nain Complex, Labrador. American Mineralogist, 61 (1-2) 29-37
Goldman, Don S., Rossman, George R. (1978) The site distribution of iron and anomalous biaxiality in osumilite. American Mineralogist, 63 (5-6) 490-498
Schreyer, W., Hentschel, G., Abraham, K. (1983) Osumilith in der Eifel und die Verwendung dieses Minerals als petrogenetischer Indikator. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 31 (3). 215-234 doi:10.1007/bf01081370
Armbruster, Thomas, Oberhänsli, Roland (1988) Crystal chemistry of double-ring silicates: Structural, chemical, and optical variation in osumilites. American Mineralogist, 73 (5-6) 585-594
Parodi, Gian Carlo, Ventura, Giancarlo Della, Lorand, Jean-pierre (1989) Mineralogy and petrology of an unusual osumilite + vanadium-rich pseudobrookite assemblage in an ejectum from the Vico Volcanic Complex (Latium, Italy) American Mineralogist, 74 (11-12) 1278-1284
Balassone, Giuseppina, Mormone, Angela, Rossi, Manuela, Bernardi, Alessandro, Fisch, Martin, Armbruster, Thomas, Malsy, Anna, Kathrin Berger, Alfons (2008) Crystal chemical and structural characterization of an Mg-rich osumilite from Vesuvius volcano (Italy) European Journal of Mineralogy, 20 (5) 713-720 doi:10.1127/0935-1221/2008/0020-1839
Seryotkin, Yurii V., Sokol, Ella V., Bakakin, Vladimir V., Likhacheva, Anna Y. (2008) Pyrometamorphic osumilite: occurrence, paragenesis, and crystal structure as compared to cordierite. European Journal of Mineralogy, 20 (2) 191-198 doi:10.1127/0935-1221/2008/0020-1805
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2012) New minerals and nomenclature modifications approved in 2012. CNMNC Newsletter No 12. Mineralogical Magazine, 76 (1) 151-155 doi:10.1180/minmag.2012.076.1.151
Chukanov, N. V., Pekov, I. V., Rastsvetaeva, R. K., Aksenov, S. M., Belakovskiy, D. I., Van, K. V., Schüller, W., Ternes, B. (2013) Osumilite-(Mg): Validation as a mineral species and new data. Geology of Ore Deposits, 55 (7) 587-593 doi:10.1134/s1075701513070064
Localities for Osumilite-(Mg)
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.
Antarctica | |
| Grew (1982) |
| Grew (1982) | |
| Grew (1982) | |
| Grew (1982) | |
| Grew (1982) |
| Grew (1982) | |
Canada | |
| Arima et al. (1991) |
| Berg et al. (1976) |
France | |
| [Barrier D et al. (2004) |
Germany | |
| Schreyer et al. (1986) |
| Schreyer et al. (1983) |
| Hentschel (1983) |
| Schreyer et al. (1983) |
| Leu (2017) |
| Schreyer et al. (1983) |
| Schreyer et al. (1983) | |
| Hentschel et al. (1977) +1 other reference |
| Blass et al. (2006) |
| Schäfer |
| Schüller |
| T. Witzke & F. Rüger: Lapis 1998 (7/8) |
Hungary | |
| GEODA 2007/1 |
India | |
| Eur. J. Mineral. |
Italy | |
| Balassone et al. (2008) |
| Parodi et al. (1989) |
| Parodi et al. (1989) | |
| Signoretti et al. (2004) +1 other reference | |
Japan | |
| Hiroaki Tano and Alfredo Petrov ... |
| Labels of several dealers at Tokyo show | |
| Kobayashi (1978) |
| Petrov (n.d.) |
| Yokomizo & Miyachi (1978) |
| Petrov (n.d.) |
New Zealand | |
| Grapes et al. (1993. Vug minerals in rhyolite, Hendersons Quarry, Mount Ngongotaha, Geological Society of New Zealand, Miscellaneous Publication 79A: 76.) |
Norway | |
| Maijer +2 other references |
| phase relations +1 other reference |
Peru | |
| Eur. J. Mineral. |
Russia | |
| Seryotkin et al. (2008) |
| Bogdanova N.G. et al. (1980) |
South Africa | |
| Nowicki et al. (1995) +1 other reference |
Uganda | |
| Eur. J. Mineral. |
UK | |
| Chinner et al. (1973) +2 other references |
USA | |
| Jerry Cone Collection |
| D.E. Russell Collection |
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Nickenicher Weinberg, Nickenich, Pellenz, Mayen-Koblenz, Rhineland-Palatinate, Germany