Roedderite
A valid IMA mineral species
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About Roedderite
Edwin W. Roedder
Formula:
K(◻Na)Mg2Mg3[Si12O30]
Colour:
Colorless, yellowish to reddish brown, sapphire blue, greenish blue
Lustre:
Vitreous
Hardness:
5 - 6
Specific Gravity:
2.6
Crystal System:
Hexagonal
Member of:
Name:
Named after Edwin Woods Roedder (30 July 1919, Monsey, New York, USA – 1 August 2006 Gloucester, Massachusetts, USA), geologist with the United States Geological Survey who earlier discovered the synthetic compound. He was a leader in the field of fluid and melt inclusions. He was awarded the 1986 Roebling Medal and the 1988 Penrose medal, and served as president of the Mineralogical Society of America.
Type Locality:
Osumilite Group. Eifelite-Roedderite Series.
Compare also almarudite, friedrichbeckeite, and UM1989-34-SiO:FeKMgMnNa.
Compare also almarudite, friedrichbeckeite, and UM1989-34-SiO:FeKMgMnNa.
Unique Identifiers
Mindat ID:
3437
Long-form identifier:
mindat:1:1:3437:7
IMA Classification of Roedderite
Approved
IMA Formula:
KNaMg2(Mg3Si12)O30
First published:
1966
Classification of Roedderite
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)
63.2.1a.14
63 : CYCLOSILICATES Condensed Rings
2 : Condensed Rings (Milarite - Osumilite group)
63 : CYCLOSILICATES Condensed Rings
2 : Condensed Rings (Milarite - Osumilite group)
14.24.4
14 : Silicates not Containing Aluminum
24 : Silicates of Fe, Mg and alkalis
14 : Silicates not Containing Aluminum
24 : Silicates of Fe, Mg 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 |
|---|---|---|
| Rdr | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Rdr | 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 |
| Roe | 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 Roedderite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colorless, yellowish to reddish brown, sapphire blue, greenish blue
Streak:
White
Hardness:
5 - 6 on Mohs scale
Cleavage:
None Observed
Density:
2.6 g/cm3 (Measured) 2.63 g/cm3 (Calculated)
Optical Data of Roedderite
Type:
Uniaxial (+)
RI values:
nω = 1.537 - 1.543 nε = 1.536 - 1.547
2V:
Measured: 2° to 5°
Max. Birefringence:
δ = 0.001 - 0.004
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
Surface Relief:
Moderate
Chemistry of Roedderite
Mindat Formula:
K(◻Na)Mg2Mg3[Si12O30]
Element Weights:
Common Impurities:
Ti,Al,Mn
Crystallography of Roedderite
Crystal System:
Hexagonal
Class (H-M):
6 m2 - Ditrigonal Dipyramidal
Space Group:
P62c
Cell Parameters:
a = 10.139(3) Å, c = 14.269(4) Å
Ratio:
a:c = 1 : 1.407
Unit Cell V:
1,270.32 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Platy to short prismatic hexagonal crystals, exhibiting dominant {1010} and {0001} with {1120}, {1012}, and {1014}.
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) |
|---|---|---|---|---|---|---|---|
| 0006360 | Roedderite | Armbruster T (1989) Crystal chemistry of double-ring silicates: structure of roedderite at 100 and 300 K T= 100 K European Journal of Mineralogy 1 715-718 | 1989 | 0 | 293 | ||
| 0006361 | Roedderite | Armbruster T (1989) Crystal chemistry of double-ring silicates: structure of roedderite at 100 and 300 K T= 300 K European Journal of Mineralogy 1 715-718 | 1989 | 0 | 293 | ||
| 0014510 | Roedderite | Alietti E, Brigatti M F, Capedri S, Poppi L (1994) The roedderite-chayesite series from Spanish lamproites: crystal chemical characterization Mineralogical Magazine 58 655-662 |  | 1994 | Cancarix, Albacete province, Spain | 0 | 293 |
| 0014513 | Roedderite | Alietti E, Brigatti M F, Capedri S, Poppi L (1994) The roedderite-chayesite series from Spanish lamproites: crystal chemical characterization Mineralogical Magazine 58 655-662 | | 1994 | Cancarix, Albacete province, Spain | 0 | 293 |
| 0014514 | Roedderite | Alietti E, Brigatti M F, Capedri S, Poppi L (1994) The roedderite-chayesite series from Spanish lamproites: crystal chemical characterization Mineralogical Magazine 58 655-662 | | 1994 | Cancarix, Albacete province, Spain | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.570 Å | (100) |
| 3.239 Å | (77) |
| 2.922 Å | (67) |
| 3.747 Å | (66) |
| 7.15 Å | (64) |
| 2.772 Å | (44) |
| 5.540 Å | (36) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 1: Primary nebular phases | 4.567-4.561 |
| 4 : Primary chondrule phases | 4.566–4.561 |
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 5 : Primary asteroid phases | 4.566–4.560 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Near-surface Processes | |
| 26 : Hadean detrital minerals |
Geological Setting:
Contact-metamorphosed basement gneiss xenoliths in leucite
tephrite.
tephrite.
Type Occurrence of Roedderite
General Appearance of Type Material:
Colorless grains. Also flat plates partly bounded laterally by faces intersecting at 120°.
Place of Conservation of Type Material:
n.d.
Geological Setting of Type Material:
Black enstatite chondrite meteorite.
Associated Minerals at Type Locality:
Synonyms of Roedderite
Other Language Names for Roedderite
Dutch:Roedderiet
German:Roedderit
Japanese:レダー石
Russian:Реддерит
Simplified Chinese:罗镁大隅石
Spanish:Roedderita
Relationship of Roedderite to other Species
Member of:
Other Members of Osumilite 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 |
| Osumilite-(Mg) | K◻2Mg2Al3[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 |
| 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 |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
| 8 photos of Roedderite associated with Hematite | Fe2O3 |
| 8 photos of Roedderite associated with Ferrosilite | Fe2+2Si2O6 |
| 4 photos of Roedderite associated with Pyroxene Group | ADSi2O6 |
| 3 photos of Roedderite associated with Pseudobrookite | Fe2TiO5 |
| 2 photos of Roedderite associated with Tridymite | SiO2 |
| 2 photos of Roedderite associated with Diopside | CaMgSi2O6 |
| 1 photo of Roedderite associated with Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| 1 photo of Roedderite associated with Magnetite | Fe2+Fe3+2O4 |
| 1 photo of Roedderite associated with Osumilite | K◻2Fe2+2Al3[Al2Si10O30] |
| 1 photo of Roedderite associated with Enstatite | Mg2Si2O6 |
Related Minerals - Strunz-mindat Grouping
| 9.CM. | Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] |
| 9.CM.05 | Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] |
| 9.CM.05 | Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] |
| 9.CM.05 | UM1990-73-SiO:KMnNaZn | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] |
| 9.CM.05 | Eifelite | KNa2(MgNa)Mg3[Si12O30] |
| 9.CM.05 | Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] |
| 9.CM.05 | Armenite | Ba(H2O)2Ca2Al3[Al3Si9O30] |
| 9.CM.05 | Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] |
| 9.CM.05 | Oftedalite | K◻2(ScCa)Be3[Si12O30] |
| 9.CM.05 | Shibkovite | K(◻K)Ca2Zn3[Si12O30] |
| 9.CM.05 | Sogdianite | K◻2Zr2Li3[Si12O30] |
| 9.CM.05 | Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] |
| 9.CM.05 | Berezanskite | K◻2Ti2Li3[Si12O30] |
| 9.CM.05 | Poudretteite | K◻2Na2B3[Si12O30] |
| 9.CM.05 | Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] |
| 9.CM.05 | Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] |
| 9.CM.05 | Osumilite-(Mg) | K◻2Mg2Al3[Al2Si10O30] |
| 9.CM.05 | Osumilite | K◻2Fe2+2Al3[Al2Si10O30] |
| 9.CM.05 | Sugilite | KNa2Fe3+2Li3[Si12O30] |
| 9.CM.05 | Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] |
| 9.CM.05 | Brannockite | K◻2Sn2Li3[Si12O30] |
| 9.CM.05 | Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] |
| 9.CM.05 | Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] |
| 9.CM.05 | Yagiite | Na◻2Mg2Al3[Al2Si10O30] |
| 9.CM.9.CM. | Aluminosugilite | KNa2Al2Li3[Si12O30] |
| 9.CM.10 | Faizievite | K2Na(Ca6Na)Ti4Li6[Si6O18]2[Si12O30]F2 |
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) | 3.9074% | 1,211 | 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
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 Roedderite
mindat.org URL:
https://www.mindat.org/min-3437.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Roedderite
Reference List:
Fuchs, Louis H., Frondel, Clifford, Klein, Jr., Cornelis (1966) Roedderite, a new mineral from the Indarch meteorite. American Mineralogist, 51 (7). 949-955
Hentschel, Gerhard, Abraham, Kurt, Schreyer, Werner (1980) First terrestrial occurrence of roedderite in volcanic ejecta of the Eifel, Germany. Contributions to Mineralogy and Petrology, 73 (2). 127-130 doi:10.1007/bf00371387
Localities for Roedderite
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 | |
| Brearley et al. (1998) |
| Krot et al. (1994) |
Austria | |
| Postl et al. (1996) |
| Postl et al. (1996) |
| Lapis 2003 (1) +1 other reference |
Azerbaijan (TL) | |
| Fuchs et al. (1966) +3 other references |
China | |
| www.lpi.usra.edu (n.d.) |
| Rambaldi et al. (1986) +1 other reference |
France | |
| Barrier D et al. (2004) |
| P & E Médard collection |
| Valverde (2009) |
Germany | |
| Rondorf et al. (1988) |
| in the collection of Christof Schäfer |
| Hentschel (1983) |
| Künzel et al. (2011) | |
| Hentschel et al. (1977) +1 other reference |
| Leu (1995) |
| Künzel |
| Schüller (1990) |
Hungary | |
| Sándor et al. (2005) |
India | |
| |
Japan | |
| ... +2 other references |
| ... +2 other references | |
| Amir Akhavan Field Observations | |
Malawi | |
| Brearley et al. (1998) |
Oman | |
| Fersman Mineralogical Museum |
Romania | |
| Krot et al. (1994) |
Spain | |
| Venturelli et al. (1984) +2 other references |
| Salvioli-Mariani et al. (1996) | |
Sudan | |
| ... |
USA | |
| Olsen et al. (1968) +1 other reference |
| rruff.geo.arizona.edu (n.d.) |
Yemen | |
| LPSC 26 (1995) +1 other reference |
Outer Space | |
| Ishii et al. (2008) |
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Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany