Rhönite
A valid IMA mineral species - grandfathered
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About Rhönite
Formula:
Ca4[Mg8Fe3+2Ti2]O4[Si6Al6O36]
Colour:
Brown-red, black to reddish black
Lustre:
Vitreous, Sub-Metallic
Hardness:
5 - 6
Specific Gravity:
3.4 - 3.76
Crystal System:
Triclinic
Member of:
Name:
Named for the type locality in the Rhön Mountains, near Fulda, Hesse, Germany.
Type Locality:
Rhönite Group.
A Ti3+-bearing analogue, one of three currently known phases with essential trivalent titanium (including tistarite and grossmanite), is known from the Allende meteorite ('UM1971-21-SiO:AlCaMgTi').
A Ti3+-bearing analogue, one of three currently known phases with essential trivalent titanium (including tistarite and grossmanite), is known from the Allende meteorite ('UM1971-21-SiO:AlCaMgTi').
Name Encoding
ASCII-7:
Rhonite
Unique Identifiers
Mindat ID:
3402
Long-form identifier:
mindat:1:1:3402:5
Similar Names
| Rheniite | A valid IMA mineral species | ReS2 |
| Rhenite | A synonym of Pseudomalachite | |
| Rhodite | A variety of Native Gold | (Au, Rh) |
| Rionite (of Brauns and Petersen) | A synonym of 'Bismuth-bearing Tetrahedrite' |
IMA Classification of Rhönite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca4(Mg8Fe3+2Ti4+2)O4[Si6Al6O36]
First published:
1907
Classification of Rhönite
9.DH.40
9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
69.2.1a.5
69 : INOSILICATES Chains with Side Branches or Loops
2 : Chains with Side Branches or Loops with P>2
69 : INOSILICATES Chains with Side Branches or Loops
2 : Chains with Side Branches or Loops with P>2
16.14.3
16 : Silicates Containing Aluminum and other Metals
14 : Aluminosilicates of Ti, Zr, Sn and Pb
16 : Silicates Containing Aluminum and other Metals
14 : Aluminosilicates of Ti, Zr, Sn and Pb
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Rhö | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Rhönite
Vitreous, Sub-Metallic
Transparency:
Translucent, Opaque
Colour:
Brown-red, black to reddish black
Streak:
Reddish brown
Hardness:
5 - 6 on Mohs scale
Cleavage:
Distinct/Good
{010}, {001}
{010}, {001}
Density:
3.4 - 3.76 g/cm3 (Measured)
Optical Data of Rhönite
Type:
Biaxial (+)
RI values:
nα = 1.795 - 1.81 nβ = 1.806 - 1.825 nγ = 1.83 - 1.845
2V:
Measured: 50° to 90°, Calculated: 70° to 84°
Max. Birefringence:
δ = 0.035
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v extreme
Pleochroism:
Strong
Comments:
X = dark greenish brown, red-brown; Y = dark reddish to greenish brown; Z = dark reddish brown to black
Chemistry of Rhönite
Mindat Formula:
Ca4[Mg8Fe3+2Ti2]O4[Si6Al6O36]
Element Weights:
Crystallography of Rhönite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 10.478 Å, b = 10.923 Å, c = 9.17 Å
α = 101.43°, β = 96.95°, γ = 129.68°
α = 101.43°, β = 96.95°, γ = 129.68°
Ratio:
a:b:c = 0.959 : 1 : 0.84
Unit Cell V:
785.9 ų
Morphology:
Prismatic or tabular crystals.
Twinning:
Polysynthetic twinning parallel to {010}, common
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.947 Å | (100) |
| 2.783 Å | (31) |
| 2.691 Å | (65) |
| 2.550 Å | (69) |
| 2.092 Å | (56) |
| 1.991 Å | (25) |
| 1.498 Å | (38) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 1: Primary nebular phases | 4.567-4.561 |
| 3 : Solar nebular condensates (CAIs, AOAs, URIs) | >4.565 |
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 8 : Mafic igneous rocks | |
| 9 : Lava/xenolith minerals (hornfels, sanidinite facies) | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Geological Setting:
Silica undersaturated, alkalic, mafic to intermediate igneous rocks.
Type Occurrence of Rhönite
Geological Setting of Type Material:
nepheline basanite
Synonyms of Rhönite
Other Language Names for Rhönite
Relationship of Rhönite to other Species
Member of:
Other Members of Rhönite Group:
| Dorrite | Ca4(Mg3Fe3+9)O4(Si3Al8Fe3+O36) | Tric. |
| Høgtuvaite | Ca4[Fe2+6Fe3+6]O4[Si8Be2Al2O36] | Tric. 1 : P1 |
| Kuratite | Ca2(Fe2+5Ti)O2[Si4Al2O18] | Tric. 1 : P1 |
| 'Leucorhönite' | Ca2(Mg,Fe3+,Al)6(Si,Al)6O20 | Tric. |
| Makarochkinite | (Ca,Na)4[Fe2+8Fe3+2Ti2]O4[Si8Be2Al2O36] | Tric. 1 : P1 |
| Serendibite | Ca4[Mg6Al6]O4[Si6B3Al3O36] | Tric. 1 : P1 |
| Welshite | Ca4Mg9Sb3O4[Si6Be3AlFe2O36] | Tric. 1 : P1 |
Common Associates
Associations Based on Photo Data:
| 23 photos of Rhönite associated with Hematite | Fe2O3 |
| 5 photos of Rhönite associated with Amphibole Supergroup | AB2C5(T8O22)W2 |
| 4 photos of Rhönite associated with Calcite | CaCO3 |
| 3 photos of Rhönite associated with Erionite Subgroup | M2[Al4Si14O36] · 15H2O |
| 2 photos of Rhönite associated with Pseudobrookite | Fe3+2Ti4+O5 |
| 2 photos of Rhönite associated with Forsterite | Mg2(SiO4) |
| 2 photos of Rhönite associated with Ilmenite | Fe2+TiO3 |
| 1 photo of Rhönite associated with Cuspidine | Ca8(Si2O7)2F4 |
| 1 photo of Rhönite associated with Gypsum | CaSO4 · 2H2O |
| 1 photo of Rhönite associated with Sanidine | K(AlSi3O8) |
Related Minerals - Strunz-mindat Grouping
| 9.DH. | Devilliersite | Ca4Ca2Fe3+10O4[(Fe3+10Si2)O36] |
| 9.DH. | 'Gageite-2M' | (Mn,Mg,Zn)42Si16O54(OH)40 |
| 9.DH. | Bavsiite | Ba2V2O2[Si4O12] |
| 9.DH. | Yuzuxiangite | Sr3Fe3+(Si2O6)2(OH) · 3H2O |
| 9.DH. | Louisfuchsite | Ca2(Mg4Ti2)(Al4Si2)O20 |
| 9.DH.05 | Leucophanite | NaCaBeSi2O6F |
| 9.DH.10 | Ohmilite | Sr3(Ti,Fe3+)(Si4O12)(O,OH) · 2-3H2O |
| 9.DH.15 | Haradaite | SrVSi2O7 |
| 9.DH.15 | Suzukiite | BaVSi2O7 |
| 9.DH.20 | Shcherbakovite | (K,Ba)KNa(Ti,Nb)2(Si4O12)O2 |
| 9.DH.20 | Batisite | BaNaNaTi2(Si4O12)O2 |
| 9.DH.20 | Noonkanbahite | BaKNaTi2(Si4O12)O2 |
| 9.DH.25 | Taikanite | Sr3BaMn2+2(Si4O12)O2 |
| 9.DH.30 | Krauskopfite | BaSi2O5 · 3H2O |
| 9.DH.35 | Gageite | Mn21(Si4O12)2O3(OH)20 |
| 9.DH.35 | Balangeroite | (Mg,Fe2+,Fe3+,Mn2+)42Si16O54(OH)40 |
| 9.DH.40 | Kuratite | Ca2(Fe2+5Ti)O2[Si4Al2O18] |
| 9.DH.40 | Aenigmatite | Na4[Fe2+10Ti2]O4[Si12O36] |
| 9.DH.40 | Dorrite | Ca4(Mg3Fe3+9)O4(Si3Al8Fe3+O36) |
| 9.DH.40 | Serendibite | Ca4[Mg6Al6]O4[Si6B3Al3O36] |
| 9.DH.40 | Khesinite | Ca4(Mg3Fe3+9)O4(Fe3+9Si3)O36 |
| 9.DH.40 | 'UM1991-29-SiO:FeMgNa' | Na4(Mg5Fe3+7)O4[Si9Fe3+3O36] |
| 9.DH.40 | Høgtuvaite | Ca4[Fe2+6Fe3+6]O4[Si8Be2Al2O36] |
| 9.DH.40 | 'Leucorhönite' | Ca2(Mg,Fe3+,Al)6(Si,Al)6O20 |
| 9.DH.40 | Welshite | Ca4Mg9Sb3O4[Si6Be3AlFe2O36] |
| 9.DH.40 | Wilkinsonite | Na2Fe2+4Fe3+2(Si6O18)O2 |
| 9.DH.40 | Krinovite | Na2Mg4Cr3+2(Si6O18)O2 |
| 9.DH.40 | Makarochkinite | (Ca,Na)4[Fe2+8Fe3+2Ti2]O4[Si8Be2Al2O36] |
| 9.DH.45 | Sapphirine | Mg4(Mg3Al9)O4[Si3Al9O36] |
| 9.DH.50 | Khmaralite | (Mg,Al,Fe)16[(Al,Si,Be)12O36]O4 |
| 9.DH.55 | 'UM1988-26-SiO:AlMg' | Mg4Al2O[Si3Al2O15] |
| 9.DH.55 | Surinamite | (Mg,Fe)3Al4BeSi3O16 |
| 9.DH.60 | Deerite | Fe2+6Fe3+3(Si6O17)O3(OH)5 |
| 9.DH.65 | Taneyamalite | (Na,Ca)Mn2+12(Si,Al)12(O,OH)44 |
| 9.DH.65 | Howieite | Na(Fe2+,Fe3+,Al,Mg)12(Si6O17)2(O,OH)10 |
| 9.DH.70 | Johninnesite | Na2Mn2+9Mg7(OH)8[AsO4]2[Si6O17]2 |
| 9.DH.75 | Agrellite | NaCa2Si4O10F |
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 Rhönite
mindat.org URL:
https://www.mindat.org/min-3402.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 Rhönite
Reference List:
Lacroix, Alfred (1909) Note sur la rhönite du Puy de Barneire à Saint-Sandoux. Bulletin de Minéralogie, 32 (7) 325-331 doi:10.3406/bulmi.1909.3374
Ficke, Bruno (1961) Petrologische Untersuchungen an tertiären basaltischen bis phonolithischen Vulkaniten der Rhön. Tschermaks Mineralogische und Petrographische Mitteilungen, 7 (4). 337-436 doi:10.1007/bf01127752
Cameron, K. L., Carman, M. F., Butler, J. C. (1970) Rhönite from Big Bend National Park, Texas. American Mineralogist, 55 (5-6) 864-874
Kyle, Philip R. (1975) Occurrences of rhonite in alkalic lavas of the McMurdo Volcanic group, Antarctica, and Dunedin Volcano, New Zealand. American Mineralogist, 60 (7-8) 722-725
Johnston, A. Dana, Stout, James H. (1984) A highly oxidized ferrian salite-, kennedyite-, forsterite-, and rhönite-bearing alkali gabbro from Kauai, Hawaii and its mantle xenoliths. American Mineralogist, 69 (1-2) 57-68
Johnston, A. Dana, Stout, James H. (1985) Compositional variation of naturally occurring rhoenite. American Mineralogist, 70 (11-12) 1211-1216
Bonaccorsi, Elena; Merlino, Stefano; Pasero, Marco (1990) Rhönite: structural and microstructural features, crystal chemistry and polysomatic relationships. European Journal of Mineralogy, 2 (2). p.203-218. doi:10.1127/ejm/2/2/0203
Jensen, B. B. (1996) Solid solution among members of the aenigmatite group. Mineralogical Magazine, 60 (403) 982-986 doi:10.1180/minmag.1996.060.403.14
Kunzmann, Thomas (1999) The aenigmatite-rhönite mineral group. European Journal of Mineralogy, 11 (4) 743-756 doi:10.1127/ejm/11/4/0743
Grapes, R. H., Wysoczanski, R. J., Hoskin, P. W. O. (2003) Rhönite paragenesis in pyroxenite xenoliths, Mount Sidley volcano, Marie Byrd Land, West Antarctica. Mineralogical Magazine, 67 (4) 639-651 doi:10.1180/0026461036740123
Grew, E. S.; Hålenius, U.; Pasero, M.; Barbier, J. (2008) Recommended nomenclature for the sapphirine and surinamite groups (sapphirine supergroup). Mineralogical Magazine, 72 (4). p.839-876. doi:10.1180/minmag.2008.072.4.839
Treiman, A. H. (2008) Rhönite in Luna 24 pyroxenes: First find from the Moon, and implications for volatiles in planetary magmas. American Mineralogist, 93 (2) 488-491 doi:10.2138/am.2008.2781
Grapes, Rodney; Keller, Jörg (2010) Fe2+-dominant rhönite in undersaturated alkaline basaltic rocks, Kaiserstuhl volcanic complex, Upper Rhine Graben, SW Germany. European Journal of Mineralogy, 22 (2). 285-292 doi:10.1127/0935-1221/2010/0022-1996
Peretyazhko, Igor S., Savina, Elena A., Khromova, Elena A. (2017) Minerals of the rhönite-kuratite series in paralavas from a new combustion metamorphic complex in the Choir–Nyalga basin (Central Mongolia): composition, mineral assemblages and formation conditions. Mineralogical Magazine, 81 (4) 949-974 doi:10.1180/minmag.2016.080.144
Localities for Rhönite
Showing 72 localities.
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.
Africa | |
| Jambon et al. (2011) |
Antarctica | |
| Kyle (1975) |
| Grapes et al. (2003) |
Argentina | |
| Jambon et al. (2011) |
Australia | |
| www.crocoite.com (2003) |
Austria | |
| Schebesta (1983) +3 other references |
| Pohl et al. (Austria) +6 other references |
Cape Verde | |
| De Ignacio et al. (2012) |
China | |
| Gupta +1 other reference |
| Kong et al. (2020) |
Czech Republic | |
| Ulrych +8 other references |
| Paulis et al. (2014) |
France | |
| Bull. Soc. Franç. Minéralo. ... |
| Bull. Soc. Franç. Minéralo. ... |
| Grünhagen et al. (1972) |
| Queneau (n.d.) |
| Hède | |
| Bailey +7 other references | |
| Havette Ledebt et al. (1982) |
Germany | |
| Walenta (1960) +2 other references |
| Weiß (1990) |
| Hentschel (1975) |
| Soellner (1907) | |
| Weiß (1990) |
| Weiß (1990) | |
| Rondorf et al. (1988) +2 other references | |
| Hentschel (1975) |
| Hentschel (1975) |
| Hentschel (1983) | |
| Blaß et al. (2015) |
| Lapis (5) +2 other references |
| Hentschel (1983) |
| Schüller et al. (1986) |
| Schüller (1990) |
| Soellner (1907) |
Greenland | |
| www.koeln.netsurf.de (1999) |
Hungary | |
| Sándor et al. (2005) |
| EGU / EGS - AGU - EUG Joint Assembly et al. (Bakony-Balaton Highland) |
| XVI ECROFI European Current Research On Fluid Inclusions et al. (Eds F. Noronha, A. Dória and A. Guedes) |
Italy | |
| perso.club-internet.fr (n.d.) |
| Alletti et al. (2005) |
Japan | |
| Monkawa et al. (2002) |
Kazakhstan | |
| |
Mexico | |
| Fuchs (1971) +1 other reference |
Mongolia | |
| Savina et al. (2020) |
| Peretyazhko et al. (2017) |
| Peretyazhko et al. (2017) |
Morocco | |
| adsabs.harvard.edu (n.d.) +3 other references |
New Zealand | |
| Kyle (1975) |
Northwest Africa Meteorites | |
| Mikouchi et al. (2003) | |
Norway | |
| Bugge et al. (1980) +1 other reference |
Pacific Ocean | |
| Peretyazhko et al. (2022) |
Poland | |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Ladenberger A. et al. (2006) |
Russia | |
| Anan’ev et al. (2011) |
| Anan’ev et al. (2011) |
| Zhitova et al. (2025) |
| 6th orogenic lherzolite conference 2014 ... | |
Slovakia | |
| Koděra et al. (1986) |
| Huraiová et al. (2007) | |
| Koděra et al. (1986) | |
| Huraiová et al. (2007) +1 other reference | |
| Koděra et al. (1986) |
South Korea | |
| Lee (ed) +7 other references | |
Spain | |
| Analyzed by XRD by Dr. Joan Vinals (Barcelona) +1 other reference |
Sweden | |
| Printzlau et al. (1972) +7 other references |
USA | |
| Johnston et al. (1984) |
| Macdonald et al. (1960) +1 other reference | |
| Cameron et al. (1970) |
Zimbabwe | |
| Kopylova et al. (1997) |
The Moon | |
| Treiman (2008) |
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Nickenicher Sattel, Nickenich, Pellenz, Mayen-Koblenz, Rhineland-Palatinate, Germany