Bavenite
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Formula:
Ca4Be2Al2Si9O26(OH)2
System:
Orthorhombic
Colour:
White
Hardness:
5½
Name:
After the type locality of Baveno, Piedmont, Italy.
Bavenite-Bohseite Series.
The composition extends from Ca4Be2Al2Si9O26(OH)2 to Ca4Be3AlSi9O25(OH)3.
The bavenite-bohseite relation is described by the following substitution scheme: O(2)OH– + T(4)Si4+ + T(3)Be2+ ↔ O(2)O2– + T(4)Al3+ + T(3)Si4+.
The composition extends from Ca4Be2Al2Si9O26(OH)2 to Ca4Be3AlSi9O25(OH)3.
The bavenite-bohseite relation is described by the following substitution scheme: O(2)OH– + T(4)Si4+ + T(3)Be2+ ↔ O(2)O2– + T(4)Al3+ + T(3)Si4+.
Classification of Bavenite
Approved, 'Grandfathered' (first described prior to 1959)
8/G.07-10
9.DF.25
9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains
9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains
70.5.3.1
70 : INOSILICATES Column or Tube Structures
5 : Column or Tube Structures with chains linked by Be
70 : INOSILICATES Column or Tube Structures
5 : Column or Tube Structures with chains linked by Be
16.6.3
16 : Silicates Containing Aluminum and other Metals
6 : Aluminosilicates of Be
16 : Silicates Containing Aluminum and other Metals
6 : Aluminosilicates of Be
Physical Properties of Bavenite
Colour:
White
Hardness (Mohs):
5½
Optical Data of Bavenite
Type:
Biaxial (+)
RI values:
nα = 1.578 - 1.586 nβ = 1.579 - 1.586 nγ = 1.583 - 1.593
2V:
Measured: 22° to 60°
Max Birefringence:
δ = 0.005 - 0.007
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v moderate
Chemical Properties of Bavenite
Formula:
Ca4Be2Al2Si9O26(OH)2
IMA Formula:
Ca4Be2+xAl2-xSi9O26-x(OH)2+x, (x=0-1)
Crystallography of Bavenite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Cell Parameters:
a = 19.39(2) Å, b = 23.19(2) Å, c = 5.005(9) Å
Ratio:
a:b:c = 0.836 : 1 : 0.216
Unit Cell Volume:
V 2,250.52 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space group Am2a (non-standard setting).
X-Ray Powder Diffraction:
Image Loading
Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
Type Occurrence of Bavenite
Relationship of Bavenite to other Species
| 9.DF.05 | Chesterite | (Mg,Fe)17Si20O54(OH)6 |
| 9.DF.05 | Clinojimthompsonite | (Mg,Fe)5Si6O16(OH)2 |
| 9.DF.05 | Jimthompsonite | (Mg,Fe)5Si6O16(OH)2 |
| 9.DF.15 | Ershovite | Na4K3(Fe,Mn,Ti)2Si8O22(OH)4 · 4H2O |
| 9.DF.15 | Paraershovite | Na3K3Fe23+Si8O20(OH)4 · 4H2O |
| 9.DF.20 | Tvedalite | (Ca,Mn)4Be3Si6O17(OH)4 · 3H2O |
| 9.DF.30 | Bigcreekite | BaSi2O5 · 4H2O |
| 16.6.1 | Beryl | Be3Al2(Si6O18) |
| 16.6.2 | Euclase | BeAl(SiO4)(OH) |
| 16.6.4 | Aminoffite | Ca2(Be,Al)(Si2O7)(H2O,OH) |
| 16.6.5 | Milarite | K2Ca4Al2Be4Si24O60 · H2O |
| 16.6.6 | Lovdarite | K2Na6Be4Si14O36 · 9H2O |
| 16.6.7 | Surinamite | (Mg,Fe)3Al4BeSi3O16 |
| 16.6.8 | Ferrotaaffeite-6N'3S | (Be,Zn,Mg)FeAl4O8 |
Other Names for Bavenite
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.
References for Bavenite
Reference List:
Schaller, Waldemar Theodore & John Gifford Fairchild (1932), Bavenite, a beryllium mineral, pseudomorphous after beryl, from California: American Mineralogist: 17: 409-422; American Mineralogist: 17: 114 (1932).
Acta Crystallographica: 20: 301-309.
Armstrong, J.A., Friis, H., Lieb, A., Finch, A.A., Weller, M.T. (2010): Combined single-crystal X-ray and neutron powder diffraction structure analysis exemplified through full structure determinations of framework and layer beryllate minerals. American Mineralogist: 95: 519-526.
A. J. Lussier and F. C. Hawthorne (2011): Short-range constraints on chemical and structural variations in bavenite. Mineralogical Magazine: 75: 213-239.
Szełęg, E., Zuzens, B., Hawthorne, F.C., Pieczka, A., Szuszkiewicz, A., Turniak, K., Nejbert, K., Ilnicki, S.S., Friis, H., Makovicky, E., Weller, M.T., Lemée-Cailleau, M.-H. (2016): Bohseite, ideally Ca4Be4Si9O24(OH)4, from the Piława Górna quarry, the Góry Sowie Block, SW Poland. Mineralogical Magazine: 80 (in press); http://forum.amiminerals.it/viewtopic.php?f=5&t=12500 (2016).
Acta Crystallographica: 20: 301-309.
Armstrong, J.A., Friis, H., Lieb, A., Finch, A.A., Weller, M.T. (2010): Combined single-crystal X-ray and neutron powder diffraction structure analysis exemplified through full structure determinations of framework and layer beryllate minerals. American Mineralogist: 95: 519-526.
A. J. Lussier and F. C. Hawthorne (2011): Short-range constraints on chemical and structural variations in bavenite. Mineralogical Magazine: 75: 213-239.
Szełęg, E., Zuzens, B., Hawthorne, F.C., Pieczka, A., Szuszkiewicz, A., Turniak, K., Nejbert, K., Ilnicki, S.S., Friis, H., Makovicky, E., Weller, M.T., Lemée-Cailleau, M.-H. (2016): Bohseite, ideally Ca4Be4Si9O24(OH)4, from the Piława Górna quarry, the Góry Sowie Block, SW Poland. Mineralogical Magazine: 80 (in press); http://forum.amiminerals.it/viewtopic.php?f=5&t=12500 (2016).
Internet Links for Bavenite
mindat.org URL:
https://www.mindat.org/min-577.html
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Baveno, Verbano-Cusio-Ossola Province, Piedmont, Italy