Magnesiocarpholite
A valid IMA mineral species
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About Magnesiocarpholite
Formula:
MgAl2Si2O6(OH)4
Colour:
Light green to grayish
Hardness:
5 - 5½
Specific Gravity:
2.88 (Calculated)
Crystal System:
Orthorhombic
Member of:
Name:
Named for being magnesium dominant carpholite.
Type Locality:
Ferrocarpholite-Magnesiocarpholite Series.
A typical low-temperature blueschist facies index mineral in metapelites.
A typical low-temperature blueschist facies index mineral in metapelites.
Unique Identifiers
Mindat ID:
2500
Long-form identifier:
mindat:1:1:2500:9
IMA Classification of Magnesiocarpholite
Approved
Approval year:
1978
First published:
1973
Classification of Magnesiocarpholite
9.DB.05
9 : SILICATES (Germanates)
D : Inosilicates
B : Inosilicates with 2-periodic single chains, Si2O6; Pyroxene-related minerals
9 : SILICATES (Germanates)
D : Inosilicates
B : Inosilicates with 2-periodic single chains, Si2O6; Pyroxene-related minerals
65.1.5.3
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
1 : Single-Width Unbranched Chains, W=1 with chains P=2
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
1 : Single-Width Unbranched Chains, W=1 with chains P=2
16.19.12
16 : Silicates Containing Aluminum and other Metals
19 : Aluminosilicates of Fe and Mg
16 : Silicates Containing Aluminum and other Metals
19 : Aluminosilicates of Fe and Mg
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 |
|---|---|---|
| Mcar | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mcar | 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 |
Physical Properties of Magnesiocarpholite
Transparency:
Transparent
Colour:
Light green to grayish
Hardness:
5 - 5½ on Mohs scale
Density:
2.88(4) g/cm3 (Calculated)
Optical Data of Magnesiocarpholite
Type:
Biaxial (-)
RI values:
nα = 1.59 nβ = 1.6 nγ = 1.61
2V:
Measured: 50° to 60°, Calculated: 88°
Max. Birefringence:
δ = 0.020
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:
Moderate (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 distinct
Chemistry of Magnesiocarpholite
Mindat Formula:
MgAl2Si2O6(OH)4
Element Weights:
Common Impurities:
Ti,Fe,Mn,Ca,Na,K,H2O,P
Crystallography of Magnesiocarpholite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Ccca
Setting:
Ccca
Cell Parameters:
a = 13.714(2) Å, b = 20.079(2) Å, c = 5.105(1) Å
Ratio:
a:b:c = 0.683 : 1 : 0.254
Unit Cell V:
1,405.73 ų (Calculated from Unit Cell)
Z:
8
Morphology:
small acicular to fibrous crystals
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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Big Balls | Small Balls | Just Balls | Spacefill
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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) |
|---|---|---|---|---|---|---|---|
| 0006871 | Magnesiocarpholite | Fuchs Y, Mellini M, Memmi I (2001) Crystal-chemistry of magnesiocarpholite: controversial X-ray diffraction, Mossbauer, FTIR and Raman results European Journal of Mineralogy 13 533-543 | 2001 | Monte Leoni | 0 | 293 | |
| 0006870 | Magnesiocarpholite | Fuchs Y, Mellini M, Memmi I (2001) Crystal-chemistry of magnesiocarpholite: controversial X-ray diffraction, Mossbauer, FTIR and Raman results European Journal of Mineralogy 13 533-543 | 2001 | Monte Argentario | 0 | 293 | |
| 0000849 | Magnesiocarpholite | Viswanathan K (1981) The crystal structure of a Mg-rich carpholite American Mineralogist 66 1080-1085 |  | 1981 | southeast Sfinari, West Crete | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.66 Å | (100) |
| 5.02 Å | (45) |
| 2.59 Å | (45) |
| 3.42 Å | (25) |
| 2.99 Å | (25) |
| 2.73 Å | (18) |
| 1.89 Å | (15) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) |
Type Occurrence of Magnesiocarpholite
Geological Setting of Type Material:
high-pressure, low-temperature metamorphism
Associated Minerals at Type Locality:
Synonyms of Magnesiocarpholite
Other Language Names for Magnesiocarpholite
Relationship of Magnesiocarpholite to other Species
Member of:
Other Members of Carpholite Group:
| Carpholite | Mn2+Al2(Si2O6)(OH)4 | Orth. mmm(2/m2/m2/m) : Ccca |
| Ferrocarpholite | Fe2+Al2Si2O6(OH)4 | Orth. mmm(2/m2/m2/m) : Ccca |
| Potassiccarpholite | K(Mn2+,Li)2Al4Si4O12(OH,F)8 | Orth. mmm(2/m2/m2/m) : Ccca |
| Vanadiocarpholite | Mn2+V3+Al(Si2O6)(OH)4 | Orth. mmm(2/m2/m2/m) : Ccca |
Forms a series with:
Related Minerals - Strunz-mindat Grouping
| 9.DB.05 | Potassiccarpholite | K(Mn2+,Li)2Al4Si4O12(OH,F)8 |
| 9.DB.05 | Carpholite | Mn2+Al2(Si2O6)(OH)4 |
| 9.DB.05 | Vanadiocarpholite | Mn2+V3+Al(Si2O6)(OH)4 |
| 9.DB.05 | Ferrocarpholite | Fe2+Al2Si2O6(OH)4 |
| 9.DB.05 | Balipholite | BaLiMg2Al3(Si2O6)2(OH)4 |
| 9.DB.10 | Lorenzenite | Na2Ti2(Si2O6)O3 |
| 9.DB.15 | Punkaruaivite | LiTi2(HSi4O12)(OH)2 · H2O |
| 9.DB.15 | Lintisite | LiNa3Ti2(Si2O6)2O2 · 2H2O |
| 9.DB.17 | Eliseevite | LiNa1.5Ti2(H1.5Si4O12)O2 · 2H2O |
| 9.DB.20 | Kukisvumite | Na6ZnTi4(Si8O24)O4 · 4H2O |
| 9.DB.20 | Manganokukisvumite | Na6MnTi4(Si8O24)O4 · 4H2O |
| 9.DB.25 | Vinogradovite | Na4Ti4(Si2O6)2[(Si,Al)4O10]O4 · (H2O,Na,K)3 |
| 9.DB.25 | Paravinogradovite | Na1-2(Ti,Fe3+)4(Si2O6)2(AlSi3O10)(OH)4 · H2O |
| 9.DB.30 | Nchwaningite | Mn2+2(SiO3)(OH)2 · H2O |
| 9.DB.40 | Shattuckite | Cu5(Si2O6)2(OH)2 |
| 9.DB.40 | 'UM2005-31-SiO:CuH' | Cu11(SiO4)(OH)18 · 9H2O (?) |
| 9.DB.45 | Aerinite | (Ca5.1Na0.5)(Fe3+,Al,Fe2+,Mg)4(Al,Mg)6[HSi12O36(OH)12][(CO3)1.2(H2O)12] |
| 9.DB.50 | Capranicaite | KCaNaAl4B4Si2O18 |
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 Magnesiocarpholite
mindat.org URL:
https://www.mindat.org/min-2500.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Magnesiocarpholite
Reference List:
Viswanathan, K., Seidel, E. (1979) Crystal chemistry of Fe-Mg-carpholites. Contributions to Mineralogy and Petrology, 70 (1) 41-47 doi:10.1007/bf00371870
Viswanathan, Krishnamoorthy (1981) The crystal structure of a Mg-rich carpholite. American Mineralogist, 66 (9-10) 1080-1085
Chopin, Christian; Goffé, Bruno (1981) High-pressure synthesis and properties of magnesiocarpholite, MgAl2[Si2O6](OH)4. Contributions to Mineralogy and Petrology, 76 (3). p.260-264. doi:10.1007/bf00375453
VIDAL, O.; GOFFÉ, B.; THEYE, T. (1992) Experimental study of the stability of sudoite and magnesiocarpholite and calculation of a new petrogenetic grid for the system FeO–MgO–Al2O3–SiO2–H2O. Journal of Metamorphic Geology, 10 (5). 603-614 doi:10.1111/j.1525-1314.1992.tb00109.x
Goffé, Bruno, Oberhänsli, Roland (1992) Ferro- and magnesiocarpholite in the “Bündnerschiefer” of the eastern Central Alps (Grisons and Engadine window). European Journal of Mineralogy, 4 (4) 835-838 doi:10.1127/ejm/4/4/0835
Fuchs, Yves; Mellini, Marcello; Memmi, Isabella (2001) Crystal-chemistry of magnesiocarpholite: controversial X-ray diffraction, Mossbauer, FTIR and Raman results. European Journal of Mineralogy, 13 (3). 533-543 doi:10.1127/0935-1221/2001/0013-0533
Agard, P., Labrousse, L., Elvevold, S., Lepvrier, C. (2005) Discovery of Paleozoic Fe-Mg carpholite in Motalafjella, Svalbard Caledonides: A milestone for subduction-zone gradients. Geology, 33 (10) 761 doi:10.1130/g21693.1
Localities for Magnesiocarpholite
Showing 29 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.
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Monte Leoni, Grosseto Province, Tuscany, Italy