Magnesiotaaffeite-6N’3S
A valid IMA mineral species
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About Magnesiotaaffeite-6N’3S
Formula:
Mg2BeAl6O12
Colour:
Colorles to pale shades of olive-green
Lustre:
Vitreous, Sub-Vitreous
Hardness:
8 - 8½
Crystal System:
Trigonal
Member of:
Name:
Re-defined by Armbruster et al. (2002) as a polysome of magnesiotaaffeite. Prior to that it was known as musgravite. The root name is in honor of Count Edward Charles Richard Taaffe, gemologist of Dublin (1898, Bohemia - 1967).
Visit gemdat.org for Name Encoding
Latin-1:
Magnesiotaaffeite-6N'3S
ASCII-7:
Magnesiotaaffeite-6N'3S
Unique Identifiers
Mindat ID:
2816
Long-form identifier:
mindat:1:1:2816:1
Similar Names
| Magnesiotaaffeite-2N’2S | A valid IMA mineral species - grandfathered | Mg3Al8BeO16 |
| Magnesiotaaffeite-2N’2S2 | Mg3BeAl8O16 |
IMA Classification of Magnesiotaaffeite-6N’3S
Approved
Classification of Magnesiotaaffeite-6N’3S
4.FC.25
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
C : Hydroxides with OH, without H2O; corner-sharing octahedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
C : Hydroxides with OH, without H2O; corner-sharing octahedra
7.2.12.1
7 : MULTIPLE OXIDES
2 : AB2X4
7 : MULTIPLE OXIDES
2 : AB2X4
7.4.6
7 : Oxides and Hydroxides
4 : Oxides of Be, Mg and the alkaline earths
7 : Oxides and Hydroxides
4 : Oxides of Be, Mg and the alkaline earths
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 for Standard |
|---|---|---|
| Mtf- 6N'3S | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mta | 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 Magnesiotaaffeite-6N’3S
Vitreous, Sub-Vitreous
Transparency:
Transparent, Translucent
Colour:
Colorles to pale shades of olive-green
Streak:
Colorless
Hardness:
8 - 8½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{0001}
{0001}
Optical Data of Magnesiotaaffeite-6N’3S
Type:
Uniaxial (-)
RI values:
nω = 1.739 nε = 1.735
Birefringence:
0.004
Max. Birefringence:
δ = 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. 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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Non-pleochroic
Chemistry of Magnesiotaaffeite-6N’3S
Mindat Formula:
Mg2BeAl6O12
Element Weights:
Elements listed:
Crystallography of Magnesiotaaffeite-6N’3S
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3m
Cell Parameters:
a = 5.67 Å, c = 41.09 Å
Ratio:
a:c = 1 : 7.247
Unit Cell V:
1,144.02 ų (Calculated from Unit Cell)
Z:
6
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) |
Type Occurrence of Magnesiotaaffeite-6N’3S
General Appearance of Type Material:
Light colored vitreous translucent mineral
Associated Minerals at Type Locality:
Synonyms of Magnesiotaaffeite-6N’3S
Other Language Names for Magnesiotaaffeite-6N’3S
Relationship of Magnesiotaaffeite-6N’3S to other Species
Member of:
Other Members of Magnesiotaaffeite subgroup:
| Magnesiotaaffeite-2N’2S | Mg3Al8BeO16 | Hex. 6/mmm(6/m2/m2/m) |
| 'Magnesiotaaffeite-2N’2S2' | Mg3BeAl8O16 | Trig. 3m(32/m) : P3m1 |
Common Associates
Associations Based on Photo Data:
| 2 photos of Magnesiotaaffeite-6N’3S associated with Pseudosinhalite | Mg2Al3(BO3)2(OH)O3 |
| 2 photos of Magnesiotaaffeite-6N’3S associated with Spinel | MgAl2O4 |
| 1 photo of Magnesiotaaffeite-6N’3S associated with Sillimanite | Al2(SiO4)O |
| 1 photo of Magnesiotaaffeite-6N’3S associated with Magnetite | Fe2+Fe3+2O4 |
Related Minerals - Strunz-mindat Grouping
| 4.FC.05 | Dzhalindite | In(OH)3 |
| 4.FC.05 | Bernalite | Fe(OH)3 · nH2O (n = 0.0 to 0.25) |
| 4.FC.05 | Söhngeite | Ga(OH)3 |
| 4.FC.10 | Mushistonite | (Cu,Zn,Fe2+)[Sn(OH)6] |
| 4.FC.10 | Natanite | Fe2+[Sn(OH)6] |
| 4.FC.10 | Burtite | Ca[Sn(OH)6] |
| 4.FC.10 | Vismirnovite | Zn[Sn(OH)6] |
| 4.FC.10 | Wickmanite | Mn2+[Sn(OH)6] |
| 4.FC.10 | Schoenfliesite | Mg[Sn(OH)6] |
| 4.FC.15 | Jeanbandyite | Fe3+Sn(OH)5O |
| 4.FC.15 | Tetrawickmanite | Mn2+[Sn4+(OH)6] |
| 4.FC.15 | Nancyrossite | FeGeO6H5 |
| 4.FC.15 | Zincostottite | ZnGe(OH)6 |
| 4.FC.15 | Stottite | Fe2+[Ge4+(OH)6] |
| 4.FC.15 | Mopungite | Na[Sb5+(OH)6] |
| 4.FC.20 | Ferronigerite-2N1S | (Al,Fe,Zn)2(Al,Sn)6O11(OH) |
| 4.FC.20 | Magnesionigerite-6N6S | (Mg,Al,Zn)3(Al,Sn,Fe)8O15(OH) |
| 4.FC.20 | Magnesionigerite-2N1S | (Mg,Al,Zn)2(Al,Sn)6O11(OH) |
| 4.FC.20 | Ferronigerite-6N6S | (Al,Fe,Zn)3(Al,Sn,Fe)8O15(OH) |
| 4.FC.20 | Zinconigerite-2N1S | (Zn,Al,Mg)2(Al,Sn)6O11(OH) |
| 4.FC.20 | Zinconigerite-6N6S | Zn3Sn2Al16O30(OH)2 |
| 4.FC.25 | Magnesiotaaffeite-2N’2S | Mg3Al8BeO16 |
| 4.FC.25 | Ferrotaaffeite-2N’2S | Be(Fe,Mg,Zn)3Al8O16 |
Fluorescence of Magnesiotaaffeite-6N’3S
Unknown if any has been tested in UV
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 Magnesiotaaffeite-6N’3S
mindat.org URL:
https://www.mindat.org/min-2816.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 Magnesiotaaffeite-6N’3S
Reference List:
Schmetzer, K. (1983) Crystal chemistry of natural Be-Mg-Al-oxides: taaffeite, taprobanite, musgravite. Neues Jahrbuch für Mineralogie - Abhandlungen, 146 (1). 15-28 doi:10.1127/njma/146/1983/15
Kiefert, Lore, Schmetzer, Karl (1998) Distinction of taaffeite and musgravite. The Journal of Gemmology, 26 (3) 165-167 doi:10.15506/jog.1998.26.3.165
Armbruster, Thomas (2002) Revised nomenclature of högbomite, nigerite, and taaffeite minerals. European Journal of Mineralogy, 14 (2) 389-395 doi:10.1127/0935-1221/2002/0014-0389
Schmetzer, Karl, Kiefert, Lore, Bernhardt, Heinz-Jürgen, Burford, Murray (2005) Musgravites from Sri Lanka. Neues Jahrbuch für Mineralogie - Abhandlungen, 181 (3) 265-270 doi:10.1127/0077-7757/2005/0021(localities)
Localities for Magnesiotaaffeite-6N’3S
Showing 11 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.
Antarctica | |
| Grew et al. (2000) |
| Grew (1981) +2 other references | |
Australia (TL) | |
| MM 1967 |
Austria | |
| Bernhard (2008) |
France | |
| Dubru. M (1986) |
Greenland | |
| Chadwick et al. (1993) +1 other reference |
Madagascar | |
| Devouard (2002) |
| fonjatany-mth.com (2016) |
Myanmar | |
| GIA/GIT gem testing & analysis. |
Sri Lanka | |
| GIA/GIT gem testing & analysis. |
Tanzania | |
| Schmetzer et al. (2007) |
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"Zircon Point" pegmatite, Khmara Bay, Casey Bay, Napier Complex, Enderby Land, East Antarctica, Antarctica