Alamosite
A valid IMA mineral species - grandfathered
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About Alamosite
Formula:
PbSiO3
Also given as Pb12(Si12O36).
Colour:
Colorless to white, cream, or light gray
Lustre:
Adamantine
Hardness:
4½
Specific Gravity:
6.488
Crystal System:
Monoclinic
Name:
Named after its discovery locality at Alamos, Mun. de Alamos, Sonora, Mexico.
Type Locality:
This page provides mineralogical data about Alamosite.
Unique Identifiers
Mindat ID:
93
Long-form identifier:
mindat:1:1:93:8
Similar Names
| Almbosite | A discredited species name | Fe52+Fe43+V46+Si3O27 |
| Lamosite | A synonym of 'Lamalginite' |
IMA Classification of Alamosite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+SiO3
First published:
1909
Classification of Alamosite
9.DO.20
9 : SILICATES (Germanates)
D : Inosilicates
O : Inosilicates with 7-, 8-, 10-, 12- and 14-periodic chains
9 : SILICATES (Germanates)
D : Inosilicates
O : Inosilicates with 7-, 8-, 10-, 12- and 14-periodic chains
65.7.1.1
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
7 : Single-Width Unbranched Chains, W=1 with chains P > 7
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
7 : Single-Width Unbranched Chains, W=1 with chains P > 7
14.13.1
14 : Silicates not Containing Aluminum
13 : Silicates of Pb
14 : Silicates not Containing Aluminum
13 : Silicates of Pb
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 |
|---|---|---|
| Aam | 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 Alamosite
Adamantine
Transparency:
Transparent, Translucent
Colour:
Colorless to white, cream, or light gray
Streak:
White
Hardness:
4½ on Mohs scale
Cleavage:
Perfect
{010}
{010}
Density:
6.488(2) g/cm3 (Measured) 6.30 g/cm3 (Calculated)
Optical Data of Alamosite
Type:
Biaxial (-)
RI values:
nα = 1.947 nβ = 1.961 nγ = 1.968
2V:
Measured: 65° , Calculated: 70°
Max. Birefringence:
δ = 0.021
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:
relatively weak
Chemistry of Alamosite
Mindat Formula:
PbSiO3
Also given as Pb12(Si12O36).
Also given as Pb12(Si12O36).
Element Weights:
Elements listed:
Common Impurities:
Al,Fe,Mn,Ca
Crystallography of Alamosite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/m
Setting:
P2/m
Cell Parameters:
a = 12.247 Å, b = 7.059 Å, c = 11.236 Å
β = 113.12°
β = 113.12°
Ratio:
a:b:c = 1.735 : 1 : 1.592
Unit Cell V:
893.35 ų (Calculated from Unit Cell)
Z:
12
Morphology:
Crystals fibrous parallel [010]; as radiating aggregates and balls, to 7.5 cm.
Comment:
P2/n
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0010657 | Alamosite | Boucher M L, Peacor D R (1968) The crystal structure of alamosite, PbSiO3 Zeitschrift fur Kristallographie 126 98-111 |  | 1968 | Alamos, Sonora, Mexico | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.34 Å | (100) |
| 3.56 Å | (95) |
| 3.53 Å | (75) |
| 2.300 Å | (75) |
| 3.23 Å | (70) |
| 2.987 Å | (70) |
| 3.25 Å | (60) |
Comments:
Tsumeb, Namibia.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Geological Setting:
As a rare secondary mineral in the oxidized zone of lead-bearing base metal deposits.
Type Occurrence of Alamosite
General Appearance of Type Material:
Radiating fibrous spheres.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 84859, 85509.
Associated Minerals at Type Locality:
Other Language Names for Alamosite
Common Associates
Associations Based on Photo Data:
| 26 photos of Alamosite associated with Melanotekite | Pb2Fe3+2(Si2O7)O2 |
| 10 photos of Alamosite associated with Kegelite | Pb8Al4(Si8O20)(SO4)2(CO3)4(OH)8 |
| 4 photos of Alamosite associated with Leadhillite | Pb4(CO3)2(SO4)(OH)2 |
| 2 photos of Alamosite associated with Willemite | Zn2SiO4 |
| 2 photos of Alamosite associated with Hematite | Fe2O3 |
| 2 photos of Alamosite associated with Quartz | SiO2 |
| 2 photos of Alamosite associated with Galena | PbS |
| 2 photos of Alamosite associated with Ganomalite | Pb9Ca5Mn(Si2O7)4(SiO4)O |
| 2 photos of Alamosite associated with 'Calcium-bearing Queitite' | (Pb,Ca)4Zn2(SO4)(SiO4)(Si2O7) |
| 2 photos of Alamosite associated with Anglesite | PbSO4 |
Related Minerals - Strunz-mindat Grouping
| 9.DO. | Braccoite | NaMn2+5[Si5As5+O17(OH)](OH) |
| 9.DO. | Illoqite-(Ce) | Na2NaBaCeZnSi6O17 |
| 9.DO.05 | Pyroxferroite | (Fe,Mn,Ca)SiO3 |
| 9.DO.05 | Pyroxmangite | Mn2+SiO3 |
| 9.DO.10 | Pellyite | Ba2CaFe2+2Si6O17 |
| 9.DO.15 | Manganonordite-(Ce) | Na3SrCeMn2+Si6O17 |
| 9.DO.15 | Ferronordite-(Ce) | Na3SrCeFe2+Si6O17 |
| 9.DO.15 | Nordite-(Ce) | (Ce,La)(Sr,Ca)Na2(Na,Mn)(Zn,Mg)Si6O17 |
| 9.DO.15 | Nordite-(La) | (La,Ce)(Sr,Ca)Na2(Na,Mn)(Zn,Mg)Si6O17 |
| 9.DO.15 | Ferronordite-(La) | Na3Sr(La,Ce)FeSi6O17 |
| 9.DO.15 | Meieranite | Na2Sr3MgSi6O17 |
| 9.DO.25 | Liebauite | Ca3Cu5Si9O26 |
| 9.DO.30 | Vladykinite | Na3Sr4(Fe2+Fe3+)Si8O24 |
| 9.DO.30 | Rundqvistite-(Ce) | Na3(Sr3Ce)[Zn2Si8O24] |
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 Alamosite
mindat.org URL:
https://www.mindat.org/min-93.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Alamosite
Reference List:
Palache, C., Merwin, Η. E. (1909) Alamosit, ein neues Bleisilicat aus Mexico. Zeitschrift für Kristallographie, 46 (1). 513-515 doi:10.1524/zkri.1909.46.1.513
Mackay, A. L. (1952) The unit cell and space-group of alamosite (PbSiO3) Mineralogical Magazine and Journal of the Mineralogical Society, 29 (218) 933-935 doi:10.1180/minmag.1952.029.218.05
Boucher, M. L., Peacor, Donald R. (1968) The crystal structure of alamosite, PbSiO3. Zeitschrift für Kristallographie, 126 (1). 98-111 doi:10.1524/zkri.1968.126.1-3.98
Cunha, T.R., Sampaio, D.V., Pena, R.B., Moulton, B.J.A., Lancelotti, R.F., Alabarse, F.G., Rodrigues, A.D., Pizani, P.S. (2022) Thermal expansion and compressibility of alamosite (PbSiO3) determined by in-situ synchrotron X-ray diffraction. Ceramics International, 48 (23) 34350-34354 doi:10.1016/j.ceramint.2022.08.012
Pena, R. B., Cunha, T. R., Gomes, E. O., Sampaio, D. V., Rodrigues, A. D., Andrés, J., Pizani, P. S. (2023) Vibrational Raman modes of alamosite (PbSiO3): Combining density functional theory calculations and in situ temperature experiments. Journal of Raman Spectroscopy, 54 (12) 1484-1489 doi:10.1002/jrs.6605
Localities for Alamosite
Showing 19 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.
Canada | |
| Caplette et al. (2015) |
Chile | |
| Zori et al. (2013) |
Germany | |
| Dill (2008) |
Mexico | |
| Smith et al. (1953) +1 other reference |
| [Amer.J.Sci. (1909) +1 other reference |
Namibia | |
| Medenbach et al. (1975) +1 other reference |
Norway | |
| Folvik (2013) |
Poland | |
| Tyszka et al. (2018) |
Sweden | |
| Holtstam et al. (1999) +2 other references |
| Nysten (2003) +1 other reference |
| Nysten (1995) +1 other reference |
Tajikistan | |
| Agakhanov et al. (2017) +1 other reference |
USA | |
| Anthony et al. (1995) |
| Raman analyzed at the University of ... +1 other reference |
| Williams (1982) |
| www.mindat.org (n.d.) |
| Williams (1982) +1 other reference |
| Anthony et al. (1995) | |
| Analyzed at the University of Western ... |
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Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia