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Cap Andrahomana, Analapatsy Commune, Taolañaro District (Fort Dauphin), Anosy Region (Fort Dauphin Region), Tuléar Province (Toliara), Madagascar

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Name(s) in local language(s):Cap Andrahomana, Kaominina Analapatsy, Distrikan' i Taolañaro, Faritra Anosy, Faritanin'i Toliary, Madagasikara
Latitude & Longitude (WGS84): 25° 11' 57'' South , 46° 37' 56'' East
Latitude & Longitude (decimal): -25.19943,46.63243
GeoHash:G#: m590thsdw
Köppen climate type:Af : Tropical rainforest climate


Cap Andrahomana is situated WSW of the town Fort Dauphin (Taolanaro), at the southernmost point of the mountainrange Chaînes Anosyennes. This is the type locality of grandidierite, where it was found in 1902 in a small pegmatite as up to 8 cm long crystals.
According to Behier (1960) C. Mignot who searched for the site, and found it (in 1960), could not find any more grandidierite at the site.
The pegmatite cross-cuts migmatitic high-grade granulite-facies (800 °C, 5-5.5 kb, 561 +/-12 Ma)metapelite gneisses and leptynites.

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Standard Detailed Strunz Dana Chemical Elements

Mineral List


12 valid minerals. 1 (TL) - type locality of valid minerals.

Rock Types Recorded

Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!

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Alphabetical List Tree Diagram

Detailed Mineral List:

Almandine
Formula: Fe2+3Al2(SiO4)3
Reference: Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. p 394
Andalusite
Formula: Al2(SiO4)O
Habit: microscopic crystals
Colour: Rose-coloured in center and colourless at the rims of the crystals
Description: Late phase.
Reference: Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. pp 403- 404
'Apatite'
Reference: Behier, J. (1963): Carte mineralogique de Madagascar. Archive Service Géologique Madagascar. A 1871
'Biotite'
Description: Late phase.
Reference: Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. p 394
Cordierite
Formula: (Mg,Fe)2Al3(AlSi5O18)
Description: Rims hercynite at the contact of quartz and feldspars.
Reference: Eur. J. Minéral; , 1991, 3, pp.367-386
Enstatite
Formula: MgSiO3
Reference: Eur. J. Minéral; , 1991, 3, pp.367-386
'Garnet Group'
Formula: X3Z2(SiO4)3
Reference: Behier, J. (1963): Carte mineralogique de Madagascar. Archive Service Géologique Madagascar. A 1871
Grandidierite (TL)
Formula: (Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
Habit: masses up to several centimeters across
Colour: Bluish green
Description: C. Mignot was not able to find any more grandidierite at the site in 1960 (Behier 1960)
Reference: Lacroix, A. (1902): Note préliminaire sur une nouvelle espèce minerale. Bulletin de la Société Francaise de Minéralogie 25: 85-86 ;
Hercynite
Formula: Fe2+Al2O4
Description: Green hercynite+quartz assemblages (high-grade metamorphism). Hercynite : 0.6% ZnO, 0.4% Cr2O3.
Reference: Eur. J. Minéral; , 1991, 3, pp.367-386
Ilmenite
Formula: Fe2+TiO3
Description: Niobian ilmenite.
Reference: http://www.mineralogicalassociation.ca/doc/abstracts/cm2_Vol36_Avr98.pdf. / p. 30
'K Feldspar'
Colour: gray
Description: perthitic
Reference: Grew, E. S. et al. (1998): Werdingite, a borosilicate new to granitic pegmatites, The Canadian Mineralogist 36, 399-414 + http://www.mineralogicalassociation.ca/doc/abstracts/cm2_Vol36_Avr98.pdf. / p. 30
Microcline
Formula: K(AlSi3O8)
Reference: Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. p 394
'Monazite'
Reference: Eur. J. Minéral; , 1991, 3, pp.367-386
'Pegmatite'
Reference: Lacroix, A. (1902): Note préliminaire sur une nouvelle espèce minerale. Bulletin de la Société Francaise de Minéralogie 25: 85-86
Quartz
Formula: SiO2
Reference: Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. p 394
Sillimanite
Formula: Al2(SiO4)O
Reference: Behier, J. (1963): Carte mineralogique de Madagascar. Archive Service Géologique Madagascar. A 1871
Spinel
Formula: MgAl2O4
Reference: Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. p 323 + 394
'UM1998-//-BOSiO:AlFeMg[2]'
Formula: (Fe2+,Mg)2Al14Si4B4O37
Reference: Grew, E. S. et al. (1998): Werdingite, a borosilicate new to granitic pegmatites, The Canadian Mineralogist 36, 399-414: AmMin 84:993
Werdingite
Formula: (Mg,Fe)2Al14Si4B4O37
Colour: Shows yellow pleochroism
Description: Be-werdingite, replaces sillimanite. Found as inclusions in grandidierite or garnet, or as grains 0,05-5mm long and 0,1-2 mm across or as 0,1-2 mm graisn replacing sillimanite.
Reference: Grew, E. S. et al. (1998): Werdingite, a borosilicate new to granitic pegmatites, The Canadian Mineralogist 36, 399-414 + [AmMin 84:993]

List of minerals arranged by Strunz 10th Edition classification

Group 4 - Oxides and Hydroxides
'Hercynite'4.BB.05Fe2+Al2O4
'Ilmenite'4.CB.05Fe2+TiO3
'Quartz'4.DA.05SiO2
'Spinel'4.BB.05MgAl2O4
Group 9 - Silicates
'Almandine'9.AD.25Fe2+3Al2(SiO4)3
'Andalusite'9.AF.10Al2(SiO4)O
'Cordierite'9.CJ.10(Mg,Fe)2Al3(AlSi5O18)
'Enstatite'9.DA.05MgSiO3
'Grandidierite' (TL)9.AJ.05(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
'Microcline'9.FA.30K(AlSi3O8)
'Sillimanite'9.AF.05Al2(SiO4)O
'Werdingite'9.BD.35(Mg,Fe)2Al14Si4B4O37
Unclassified Minerals, Rocks, etc.
'Apatite'-
'Biotite'-
'Garnet Group'-X3Z2(SiO4)3
'K Feldspar'-
'Monazite'-
'Pegmatite'-
'UM1998-//-BOSiO:AlFeMg[2]'-(Fe2+,Mg)2Al14Si4B4O37

List of minerals arranged by Dana 8th Edition classification

Group 4 - SIMPLE OXIDES
A2X3
Ilmenite4.3.5.1Fe2+TiO3
Group 7 - MULTIPLE OXIDES
AB2X4
Hercynite7.2.1.3Fe2+Al2O4
Spinel7.2.1.1MgAl2O4
Group 51 - NESOSILICATES Insular SiO4 Groups Only
Insular SiO4 Groups Only with cations in [6] and >[6] coordination
Almandine51.4.3a.2Fe2+3Al2(SiO4)3
Group 52 - NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
Andalusite52.2.2b.1Al2(SiO4)O
Sillimanite52.2.2a.1Al2(SiO4)O
Group 54 - NESOSILICATES Borosilicates and Some Beryllosilicates
Borosilicates and Some Beryllosilicates with (BO3)
Grandidierite (TL)54.1.1.1(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
Group 56 - SOROSILICATES Si2O7 Groups, With Additional O, OH, F and H2O
Si2O7 Groups and O, OH, F, and H2O with[Si2O7] with borate groups
Werdingite56.3.2.1(Mg,Fe)2Al14Si4B4O37
Group 61 - CYCLOSILICATES Six-Membered Rings
Six-Membered Rings with Al substituted rings
Cordierite61.2.1.1(Mg,Fe)2Al3(AlSi5O18)
Group 65 - INOSILICATES Single-Width,Unbranched Chains,(W=1)
Single-Width Unbranched Chains, W=1 with chains P=2
Enstatite65.1.2.1MgSiO3
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Quartz75.1.3.1SiO2
Group 76 - TECTOSILICATES Al-Si Framework
Al-Si Framework with Al-Si frameworks
Microcline76.1.1.5K(AlSi3O8)
Unclassified Minerals, Rocks, etc.
'Apatite'-
'Biotite'-
'Garnet Group'-X3Z2(SiO4)3
'K Feldspar'-
'Monazite'-
'Pegmatite'-
'UM1998-//-BOSiO:AlFeMg[2]'-(Fe2+,Mg)2Al14Si4B4O37

List of minerals for each chemical element

BBoron
B Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
B UM1998-//-BOSiO:AlFeMg[2](Fe2+,Mg)2Al14Si4B4O37
B Werdingite(Mg,Fe)2Al14Si4B4O37
OOxygen
O AlmandineFe32+Al2(SiO4)3
O AndalusiteAl2(SiO4)O
O Cordierite(Mg,Fe)2Al3(AlSi5O18)
O EnstatiteMgSiO3
O Garnet GroupX3Z2(SiO4)3
O Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
O HercyniteFe2+Al2O4
O IlmeniteFe2+TiO3
O MicroclineK(AlSi3O8)
O QuartzSiO2
O SillimaniteAl2(SiO4)O
O SpinelMgAl2O4
O UM1998-//-BOSiO:AlFeMg[2](Fe2+,Mg)2Al14Si4B4O37
O Werdingite(Mg,Fe)2Al14Si4B4O37
MgMagnesium
Mg Cordierite(Mg,Fe)2Al3(AlSi5O18)
Mg EnstatiteMgSiO3
Mg Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
Mg SpinelMgAl2O4
Mg UM1998-//-BOSiO:AlFeMg[2](Fe2+,Mg)2Al14Si4B4O37
Mg Werdingite(Mg,Fe)2Al14Si4B4O37
AlAluminium
Al AlmandineFe32+Al2(SiO4)3
Al AndalusiteAl2(SiO4)O
Al Cordierite(Mg,Fe)2Al3(AlSi5O18)
Al Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
Al HercyniteFe2+Al2O4
Al MicroclineK(AlSi3O8)
Al SillimaniteAl2(SiO4)O
Al SpinelMgAl2O4
Al UM1998-//-BOSiO:AlFeMg[2](Fe2+,Mg)2Al14Si4B4O37
Al Werdingite(Mg,Fe)2Al14Si4B4O37
SiSilicon
Si AlmandineFe32+Al2(SiO4)3
Si AndalusiteAl2(SiO4)O
Si Cordierite(Mg,Fe)2Al3(AlSi5O18)
Si EnstatiteMgSiO3
Si Garnet GroupX3Z2(SiO4)3
Si Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
Si MicroclineK(AlSi3O8)
Si QuartzSiO2
Si SillimaniteAl2(SiO4)O
Si UM1998-//-BOSiO:AlFeMg[2](Fe2+,Mg)2Al14Si4B4O37
Si Werdingite(Mg,Fe)2Al14Si4B4O37
KPotassium
K MicroclineK(AlSi3O8)
TiTitanium
Ti IlmeniteFe2+TiO3
FeIron
Fe AlmandineFe32+Al2(SiO4)3
Fe Cordierite(Mg,Fe)2Al3(AlSi5O18)
Fe Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
Fe HercyniteFe2+Al2O4
Fe IlmeniteFe2+TiO3
Fe UM1998-//-BOSiO:AlFeMg[2](Fe2+,Mg)2Al14Si4B4O37

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Lacroix, A. (1902): Note préliminaire sur une nouvelle espèce minerale. Bulletin de la Société Francaise de Minéralogie 25: 85-86
Lacroix, A. (1922): Mineralogie de Madagascar, Tome I. Géologie-Minéralogie descriptive. A.Challamel (Éditeur), Paris. 624p
Decary, R. (1927?): Les Gneiss à Grandidierite d'Andrahomana (Madagascar). Bulletin du Museum national d'histoire naturelle; 1ère Série; Tome 33, 556-557
Behier, J. (1960): Travaux mineralogiques. in Besaire,H. (ed): Rapport Annuel du Service Geologique pour 1960. Republique Malgache, 181-199 [p. 194, note on a search for grandidierite in 1960]
Behier, J. (1963): Carte mineralogique de Madagascar. Archive Service Géologique Madagascar. A 1871
Eur. J. Minéral; , 1991, 3, pp.367-386
Grew, E. S.; Yates, M. G. ; Huijsmans, J. P. P. ; McGee, J. J.; Shearer, C. K.; Wiedenbeck, M. & Rouse, R. C. (1998): Werdingite, a borosilicate new to granitic pegmatites, The Canadian Mineralogist 36, 399-414


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