Axinite-(Mg)
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Axinite-(Mg)
Formula:
Ca2MgAl2BSi4O15OH
Colour:
Colourless, pale blue, lavender, pink, brown
Lustre:
Vitreous
Hardness:
6½ - 7
Specific Gravity:
3.16
Crystal System:
Triclinic
Member of:
Name:
From the Greek αξίνα ("axina") for "axe", in allusion to the common habit of its crystals, and magnesium dominance in the formula.
Axinite Group. The magnesium analogue of Axinite-(Fe) and Axinite-(Mn).
Visit gemdat.org for gemological information about Axinite-(Mg).
Visit gemdat.org for gemological information about Axinite-(Mg).Unique Identifiers
Mindat ID:
2490
Long-form identifier:
mindat:1:1:2490:3
Similar Names
| Axinit | A synonym of 'Axinite' | |
| Axinite | A synonym of Axinite Group | |
| Axinite-(Fe) | A valid IMA mineral species - grandfathered | Ca2Fe2+Al2BSi4O15OH |
| Axinite-(Fe)-Axinite-(Mn) Series | A solid-solution series between two end-member minerals | |
| Axinite-(Mn) | A valid IMA mineral species - grandfathered | Ca2Mn2+Al2BSi4O15(OH) |
| Axinite-(Mn)-Tinzenite Series | A solid-solution series between two end-member minerals |
IMA Classification of Axinite-(Mg)
Classification of Axinite-(Mg)
9.BD.20
9 : SILICATES (Germanates)
B : Sorosilicates
D : Si2O7 groups, with additional anions; cations in tetrahedral [4] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
D : Si2O7 groups, with additional anions; cations in tetrahedral [4] and greater coordination
56.2.2.2
56 : SOROSILICATES Si2O7 Groups, With Additional O, OH, F and H2O
2 : Si2O7 Groups and O, OH, F, and H2O with cations in [4] and/or >[4] coordination
56 : SOROSILICATES Si2O7 Groups, With Additional O, OH, F and H2O
2 : Si2O7 Groups and O, OH, F, and H2O with cations in [4] and/or >[4] coordination
17.5.29
17 : Silicates Containing other Anions
5 : Borosilicates
17 : Silicates Containing other Anions
5 : Borosilicates
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 |
|---|---|---|
| Ax-Mg | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Ax | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Ax | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
| Ax | 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 |
Pronunciation of Axinite-(Mg)
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Axinite-(Mg)
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless, pale blue, lavender, pink, brown
Streak:
White
Hardness:
6½ - 7 on Mohs scale
Density:
3.16(1) g/cm3 (Measured) 3.167 g/cm3 (Calculated)
Optical Data of Axinite-(Mg)
Type:
Biaxial (-)
RI values:
nα = 1.672 - 1.693 nβ = 1.677 - 1.701 nγ = 1.681 - 1.704
2V:
Measured: 69° to 87°, Calculated: 62° to 82°
Max. Birefringence:
δ = 0.009 - 0.011
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:
strong
Chemistry of Axinite-(Mg)
Mindat Formula:
Ca2MgAl2BSi4O15OH
Element Weights:
Common Impurities:
Ti,V,Mn,Zn,K,H2O
Crystallography of Axinite-(Mg)
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 7.1381(3) Å, b = 9.1626(4) Å, c = 8.9421(4) Å
α = 91.903(4)°, β = 98.105(3)°, γ = 77.468(4)°
α = 91.903(4)°, β = 98.105(3)°, γ = 77.468(4)°
Ratio:
a:b:c = 0.779 : 1 : 0.976
Unit Cell V:
565.21 ų (Calculated from Unit Cell)
Z:
2
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0006850 | Axinite-(Mg) | Andreozzi G B, Lucchesi S, Graziani G (2000) Structural study of magnesioaxinite and its crystal-chemical relations with axinite-group minerals European Journal of Mineralogy 12 1185-1194 | 2000 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.95 Å | (15) |
| 6.29 Å | (25) |
| 4.96 Å | (4) |
| 4.76 Å | (8) |
| 4.61 Å | (2) |
| 3.97 Å | (10) |
| 3.66 Å | (5) |
| 3.44 Å | (65) |
| 3.27 Å | (20) |
| 3.14 Å | (65) |
| 3.07 Å | (8) |
| 2.985 Å | (20b) |
| 2.877 Å | (20) |
| 2.796 Å | (100) |
| 2.753 Å | (5b) |
| 2.633 Å | (5) |
| 2.556 Å | (25) |
| 2.429 Å | (18) |
| 2.415 Å | (18) |
| 2.452 Å | (8) |
| 2.305 Å | (1) |
| 2.252 Å | (1) |
| 2.176 Å | (30) |
| 2.150 Å | (30) |
| 2.121 Å | (4) |
| 2.048 Å | (14) |
| 2.028 Å | (14) |
Comments:
ICDD 29-344, natural material, Tanzania
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Axinite-(Mg)
Synonyms of Axinite-(Mg)
Other Language Names for Axinite-(Mg)
Dutch:Axiniet-(Mg)
Esperanto:Magnezioaksinito
French:Axinite-(Mg)
German:Axinit-(Mg)
Magnesio-Axinit
Magnesio-Axinit
Japanese:苦土斧石
Norwegian:Axinitt-(Mg)
Russian:Магнезиоаксинит
Аксинит-(Mg)
Аксинит-(Mg)
Relationship of Axinite-(Mg) to other Species
Member of:
Other Members of Axinite Group:
| Axinite-(Fe) | Ca2Fe2+Al2BSi4O15OH | Tric. 1 : P1 |
| Axinite-(Mn) | Ca2Mn2+Al2BSi4O15(OH) | Tric. 1 : P1 |
| Tinzenite | Ca2Mn2+4Al4[B2Si8O30](OH)2 | Tric. 1 : P1 |
Common Associates
Related Minerals - Strunz-mindat Grouping
| 9.BD.05 | Bertrandite | Be4(Si2O7)(OH)2 |
| 9.BD.10 | Hemimorphite | Zn4Si2O7(OH)2 · H2O |
| 9.BD.15 | Junitoite | CaZn2Si2O7 · H2O |
| 9.BD.20 | Tinzenite | Ca2Mn2+4Al4[B2Si8O30](OH)2 |
| 9.BD.20 | Axinite-(Fe) | Ca2Fe2+Al2BSi4O15OH |
| 9.BD.20 | Dubińskaite | Ca4Sc2Al4[Be2Si8O30](OH)2 |
| 9.BD.20 | Axinite-(Mn) | Ca2Mn2+Al2BSi4O15(OH) |
| 9.BD.25 | Vistepite | SnMn4B2Si4O16(OH)2 |
| 9.BD.30 | Boralsilite | Al16B6O30(Si2O7) |
| 9.BD.35 | Werdingite | (Mg,Fe)2Al14Si4B4O37 |
| 9.BD.40 | Vránaite | Al16B4Si4O38 |
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 Axinite-(Mg)
mindat.org URL:
https://www.mindat.org/min-2490.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Axinite-(Mg)
Reference List:
Fleischer, Michael, Cabri, Louis J. (1976) New Mineral names. American Mineralogist, 61 (5-6) 502-504 pp.503-504
Lumpkin, Gregory R., Ribbe, Paul H. (1979) Chemistry and physical properties of axinites. American Mineralogist, 64 (5-6) 635-645
Salviulo, Gabriella; Andreozzi, Giovanni B.; Graziani, Giorgio (2000) X-ray characterization of Mg, Fe, and Mn natural end-members of the axinite group. Powder Diffraction, 15 (3). 180-188 doi:10.1017/s0885715600011040
Localities for Axinite-(Mg)
Showing 20 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.
Australia | |
| Leavens et al. (1980) +1 other reference |
| R. Bottrill |
Austria | |
| Niedermayr (2002) |
| Niedermayr (1996) |
Czech Republic | |
| Novák et al. (2002) |
| Dolníček Z et al. (2020) |
Japan | |
| Matsubara et al. (2011) |
Namibia | |
| Grolig (2005) +1 other reference |
Romania | |
| HÎRTOPANU et al. (2025) |
Russia | |
| Erokhin et al. (2007) |
Spain | |
| Calvo Rebollar (2018) |
Sweden | |
| Gatedal (2003) |
Switzerland | |
| |
Tanzania | |
| Mineralogical Society of America - ... | |
| P Bongaerts collection +2 other references |
| Photo ID: 379162 | |
USA | |
| Chris Stefano |
| Heinrich et al. (2004) |
| Rocks & Minerals. Nov. 1999. |
| Leavens et al. (1980) |
Quick NavTopAbout Axinite-(Mg)Unique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPronunciation Physical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania