Grandaite
A valid IMA mineral species
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About Grandaite
Formula:
Sr2Al(AsO4)2(OH)
Colour:
Bright orange to salmon to brown colour
Lustre:
Vitreous, Waxy
Hardness:
6 - 6½
Specific Gravity:
4.378 (Calculated)
Crystal System:
Monoclinic
Member of:
Name:
Due to its size, Cuneo Province is known in Piedmont by the nickname "Provincia Granda" or, more simply, "la Granda" (i.e., The Large One). The mineral is named after this informal appellation of the province that includes the type locality.
Unique Identifiers
Mindat ID:
45951
Long-form identifier:
mindat:1:1:45951:2
Similar Names
| Granatit | A synonym |
| Grandit | A synonym of 'Grandite' |
| Grandite | A synonym of 'Andradite-Grossular Series' |
| Grenatite | A synonym |
| Grenatite (of Daubenton) | A synonym of Leucite |
| Grännaite | A synonym of 'Grennaite' |
IMA Classification of Grandaite
Approved
IMA Formula:
Sr2+2Al(As5+O4)2(OH)
Approval year:
2013
First published:
2014
Type description reference:
Cámara, F., Ciriotti, M. E., Bittarello, E., Nestola, F., Massimi, F., Radica, F., Costa, E., Benna, P., Piccoli, G. C. (2014) Arsenic-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure. Mineralogical Magazine, 78 (3) 757-774 doi:10.1180/minmag.2014.078.3.21
Classification of Grandaite
8.00.
8 : PHOSPHATES, ARSENATES, VANADATES
0 :
0 :
8 : PHOSPHATES, ARSENATES, VANADATES
0 :
0 :
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 |
|---|---|---|
| Grd | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Grandaite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Grandaite
Vitreous, Waxy
Colour:
Bright orange to salmon to brown colour
Streak:
Reddish brown
Hardness:
6 - 6½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
None observed
Fracture:
Irregular/Uneven
Density:
4.378 g/cm3 (Calculated)
Comment:
Not measured due to small crystal size and intergrowths
Optical Data of Grandaite
Type:
Biaxial (+)
RI values:
nα = 1.726(1) nβ = 1.731(1) nγ = 1.752(1)
2V:
Measured: 52° (2), Calculated: 53°
Max. Birefringence:
δ = 0.026
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
Pleochroism:
Non-pleochroic
Chemistry of Grandaite
Mindat Formula:
Sr2Al(AsO4)2(OH)
Element Weights:
Crystallography of Grandaite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P21/m
Cell Parameters:
a = 7.5764(5) Å, b = 5.9507(4) Å, c = 8.8050(6) Å
β = 112.551(2)°
β = 112.551(2)°
Ratio:
a:b:c = 1.273 : 1 : 1.48
Unit Cell V:
366.62 ų
Z:
2
Morphology:
Platy tablets.
Twinning:
None observed
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.194 Å | (100) |
| 2.981 Å | (51) |
| 2.922 Å | (40) |
| 2.743 Å | (31) |
| 2.705 Å | (65) |
| 2.087 Å | (52) |
| 1.685 Å | (25) |
| 1.663 Å | (13) |
Reference:
Cámara, F., Ciriotti, M. E., Bittarello, E., Nestola, F., Massimi, F., Radica, F., Costa, E., Benna, P., Piccoli, G. C. (2014) Arsenic-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure. Mineralogical Magazine, 78 (3) 757-774 doi:10.1180/minmag.2014.078.3.21
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 46 : Near-surface hydrothermal alteration of minerals (see also #22) |
Type Occurrence of Grandaite
General Appearance of Type Material:
Thin masses or as fan-like aggregates of small (< 1 mm) crystals
Place of Conservation of Type Material:
Museo Regionale di Scienze Naturali di Torino, Sezione di Mineralogia, Petrografia e Geologia, Torino, Italy, catalogue number M/ 15999.
Museo Civico Archeologico e di Scienze Naturali, Alba, Cuneo, Italy, catalogue number G. 1723 prog. 505.
Museo Civico Archeologico e di Scienze Naturali, Alba, Cuneo, Italy, catalogue number G. 1723 prog. 505.
Geological Setting of Type Material:
Reaction between the ore minerals and hydrothermal solutions, found on the dumps of Valetta Mine.
Associated Minerals at Type Locality:
Reference:
Cámara, F., Ciriotti, M. E., Bittarello, E., Nestola, F., Massimi, F., Radica, F., Costa, E., Benna, P., Piccoli, G. C. (2014) Arsenic-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure. Mineralogical Magazine, 78 (3) 757-774 doi:10.1180/minmag.2014.078.3.21
Synonyms of Grandaite
Other Language Names for Grandaite
Relationship of Grandaite to other Species
Member of:
Other Members of Brackebuschite Supergroup:
| Aldomarinoite | Sr2Mn3+(AsO4)2(OH) | Mon. 2/m : P21/m |
| Arsenbrackebuschite | Pb2Fe3+(AsO4)2(OH) | Mon. 2/m : P2/m |
| Arsentsumebite | Pb2Cu(AsO4)(SO4)(OH) | Mon. 2/m : P21/m |
| Bearthite | Ca2Al(PO4)2(OH) | Mon. 2/m : P21/m |
| Brackebuschite | Pb2Mn3+(VO4)2(OH) | Mon. 2/m : P21/m |
| Bushmakinite | Pb2Al(PO4)(VO4)(OH) | Mon. 2/m : P21/m |
| Calderónite | Pb2Fe3+(VO4)2(OH) | Mon. 2/m : P21/m |
| Canosioite | Ba2Fe3+(AsO4)2(OH) | Mon. 2/m : P21/m |
| Feinglosite | Pb2Zn(AsO4)2 · H2O | Mon. 2/m |
| Ferribushmakinite | Pb2Fe3+(PO4)(VO4)(OH) | Mon. 2/m : P21/m |
| Gamagarite | Ba2Fe3+(VO4)2(OH) | Mon. 2/m : P21/m |
| Goedkenite | Sr2Al(PO4)2(OH) | Mon. 2/m : P21/m |
| Lombardoite | Ba2Mn3+(AsO4)2(OH) | Mon. 2/m : P21/m |
| Tokyoite | Ba2Mn3+(VO4)2(OH) | Mon. 2/m : P21/m |
| Tsumebite | Pb2Cu(PO4)(SO4)(OH) | Mon. 2/m : P21/m |
| 'Unnamed (possible ordered As-analogue of Tokyoite)' | Ba2Mn[(As,V)O4]2(OH) | Mon. 2/m : P21/m |
Common Associates
Associations Based on Photo Data:
| 1 photo of Grandaite associated with Quartz | SiO2 |
| 1 photo of Grandaite associated with Piccoliite | NaCaMn3+2(AsO4)2O(OH) |
Related Minerals - Strunz-mindat Grouping
| 8.00. | Canutite | NaMn3[AsO4][AsO3(OH)]2 |
| 8.00. | Metauramphite | (NH4)2(UO2)2(PO4)2.6H2O |
| 8.00. | Strontiohurlbutite | SrBe2(PO4)2 |
| 8.00. | Chongite | Ca3Mg2(AsO4)2(AsO3OH)2 · 4H2O |
| 8.00. | 'UM1997-10-AsO:CaV' | Ca(VO)2(AsO4)2.4H2O |
| 8.00.05 | 'Leobenite' | Hydrated Ca-Fe phosphate |
Fluorescence of Grandaite
Does not fluoresce under LW or SW UV
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 Grandaite
mindat.org URL:
https://www.mindat.org/min-45951.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Grandaite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No 18. Mineralogical Magazine, 77 (8) 3249-3258 doi:10.1180/minmag.2013.077.8.15
Cámara, F., Ciriotti, M. E., Bittarello, E., Nestola, F., Massimi, F., Radica, F., Costa, E., Benna, P., Piccoli, G. C. (2014) Arsenic-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure. Mineralogical Magazine, 78 (3) 757-774 doi:10.1180/minmag.2014.078.3.21
Localities for Grandaite
Showing 2 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.
Italy | |
| Castellaro et al. (2021) |
| www.socgeol.it (n.d.) +4 other references |
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Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy