Andrémeyerite
A valid IMA mineral species
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About Andrémeyerite
Formula:
BaFe2+2(Si2O7)
Colour:
light emerald-green
Hardness:
5½
Specific Gravity:
4.15
Crystal System:
Monoclinic
Name:
To honor André Marie Meyer (Turku, Finland, October 13 1920 - Libreville, Gabon, January 10 1965), Belgian geologist with the Geological Survey of the Belgian Congo, who first collected the mineral. His publications were essentially devoted to igneous rocks from Kivu, in particular to lava flows of the Nyiragongo and Nyamuragira volcanoes, as well to the rocks forming the syenite-carbonatite complex of the Lueshe (Der Meersche et al. 2010).
This page provides mineralogical data about Andrémeyerite.
Name Encoding
ASCII-7:
Andremeyerite
Unique Identifiers
Mindat ID:
225
Long-form identifier:
mindat:1:1:225:3
IMA Classification of Andrémeyerite
Approved
IMA Formula:
BaFe2+2Si2O7
Approval year:
1972
Classification of Andrémeyerite
9.BB.20
9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
56.2.6c.6
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
14.7.8
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
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 |
|---|---|---|
| Amy | 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 Andrémeyerite
Transparency:
Transparent, Translucent
Colour:
Light emerald-green
Hardness:
5½ on Mohs scale
Hardness:
VHN100=440 - Vickers
Cleavage:
Perfect
Perfect on {100} and {010}
Perfect on {100} and {010}
Density:
4.15 g/cm3 (Measured) 4.14 g/cm3 (Calculated)
Optical Data of Andrémeyerite
Type:
Biaxial (+)
RI values:
nα = 1.74 nβ = 1.74 nγ = 1.76
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.
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
Dispersion:
r > v moderate
Pleochroism:
Visible
Comments:
X = pale bluish green; Y = Z = colorless with faint brownish tint.
Chemistry of Andrémeyerite
Mindat Formula:
BaFe2+2(Si2O7)
Element Weights:
Elements listed:
Common Impurities:
Al,Mn,Mg,Ca,Na,K
Crystallography of Andrémeyerite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 7.488(1) Å, b = 13.785(1) Å, c = 7.085(1) Å
β = 118.23(1)°
β = 118.23(1)°
Ratio:
a:b:c = 0.543 : 1 : 0.514
Unit Cell V:
644.34 ų (Calculated from Unit Cell)
Z:
4
Morphology:
As crystals, < 0.2 mm, with {100} and {010} dominant, also {011} and {120}.
Twinning:
Multiple twinning on {100}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.055 Å | (100) |
| 3.122 Å | (80) |
| 3.288 Å | (60) |
| 2.472 Å | (55) |
| 4.63 Å | (40) |
| 2.811 Å | (40) |
| 3.198 Å | (20) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 56 : Slag and smelter minerals (see also #51 and #55) |
Type Occurrence of Andrémeyerite
General Appearance of Type Material:
As crystals, < 0.2 mm
Place of Conservation of Type Material:
University of Helsinki, Helsinki, Finland.
Canillo (1988) examined the crystal structure using matarial provided by Thure Sahama: this could explain the absence of any holotype material in the present-day collection in Helsinki.
Canillo (1988) examined the crystal structure using matarial provided by Thure Sahama: this could explain the absence of any holotype material in the present-day collection in Helsinki.
Geological Setting of Type Material:
In vesicles of melilite-leucite-nephelinite; may represent crystallization of an associated green glass.
Associated Minerals at Type Locality:
Synonyms of Andrémeyerite
Other Language Names for Andrémeyerite
Dutch:Andrémeyeriet
French:Andrémeyerite
German:Andrémeyerit
Andremeyerit
Andremeyerit
Norwegian:Andrémeyeritt
Russian:Андремейерит
Spanish:Andremeyerita
Common Associates
Associations Based on Photo Data:
| 2 photos of Andrémeyerite associated with Melilite Group | Ca2M(XSiO7) |
| 1 photo of Andrémeyerite associated with Nepheline | Na3K(Al4Si4O16) |
Related Minerals - Strunz-mindat Grouping
| 9.BB.10 | Hardystonite | Ca2Zn[Si2O7] |
| 9.BB.10 | Okayamalite | Ca2B[BSiO7] |
| 9.BB.10 | Jeffreyite | (Ca,Na)2(Be,Al)(Si2O7,HSi2O7) |
| 9.BB.10 | Alumoåkermanite | (CaNa)Al[Si2O7] |
| 9.BB.10 | Åkermanite | Ca2Mg[Si2O7] |
| 9.BB.10 | 'Ferri-gehlenite' | Ca2Fe3+[AlSiO7] |
| 9.BB.10 | Gehlenite | Ca2Al[AlSiO7] |
| 9.BB.10 | Ferroåkermanite | Ca2Fe[Si2O7] |
| 9.BB.10 | Cebollite | Ca5Al2(SiO4)3(OH)4 |
| 9.BB.10 | Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] |
| 9.BB.10 | Gugiaite | Ca2Be[Si2O7] |
| 9.BB.15 | Barylite | Be2Ba(Si2O7) |
| 9.BB.15 | 'Barylite-1O' | Be2Ba(Si2O7) |
| 9.BB.20 | Bennesherite | Ba2Fe2+[Si2O7] |
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 Andrémeyerite
mindat.org URL:
https://www.mindat.org/min-225.html
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Please feel free to link to this page.
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References for Andrémeyerite
Reference List:
Sahama, Th.G., Siivola, J., Rehtijärvi, P. (1973) Andremeyerite, a new barium iron silicate, from Nyiragongo, Zaire. Bulletin of the Geological Society of Finland, 45 (1). 1-8 doi:10.17741/bgsf/45.1.001
Fleischer, Michael; Mandarino, Joseph A (1974) New mineral names. American Mineralogist, 59 (3-4). 381-384 [abstract of Sahama et al. 1973]
Localities for Andrémeyerite
Showing 3 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.
Austria | |
| Kolitsch et al. (2013) |
Czech Republic | |
| Jirasek et al. (2026) |
DR Congo (TL) | |
| Richard +16 other references |
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Podhorní hill, Ovesné Kladruby, Cheb District, Karlovy Vary Region, Czech Republic