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Zazafotsy Quarry (Amboarohy), Zazafotsy, Ihosy District, Ihorombe, Madagascari
Regional Level Types
Zazafotsy Quarry (Amboarohy)Quarry
ZazafotsyCommune
Ihosy DistrictDistrict
IhorombeRegion
MadagascarCountry

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Latitude & Longitude (WGS84):
22° 8' 9'' South , 46° 26' 14'' East
Latitude & Longitude (decimal):
Type:
Age:
494 ± 5 Ma
Geologic Time:
Dating method:
Ar – Ar biotite
Reference for age:
Giuliani, Gaston, Fallick, Anthony, Rakotondrazafy, Michel, Ohnenstetter, Daniel, Andriamamonjy, Alfred, Ralantoarison, Théogène, Rakotosamizanany, Saholy, Razanatseheno, Marie, Offant, Yohann, Garnier, Virginie, Dunaigre, Christian, Schwarz, Dietmar, Mercier, Alain, Ratrimo, Voahangy, Ralison, Bruno (2007) Oxygen isotope systematics of gem corundum deposits in Madagascar: relevance for their geological origin. Mineralium Deposita, 42 (3). 251-270 doi:10.1007/s00126-006-0105-3
Köppen climate type:
Nearest Settlements:
PlacePopulationDistance
Ihosy16,990 (2018)43.7km
Ambalavao28,027 (2018)61.2km
Mindat Locality ID:
27844
Long-form identifier:
mindat:1:2:27844:6
GUID (UUID V4):
d7732716-37e9-455b-88b4-e661730d35c4
Other Languages:
Malagasy:
Amboarohy (Ambahatraso), Kaominin'i Zazafotsy, Distrikan' Ihosy, Faritr' Ihorombe, Madagasikara


Granulite-facies pelites. Deposit famous for polychromatic corundum crystals.
Located about 35 km N of Ihosy following the RN 7 to Ambalavao. Popularly called "Zazafotsy quarry" which also is the name of the village along RN 7 and the center of the Zazafotsy Commune, but originally called Amboarohy (Pezzotta 2005).

The locality was discovered in the late 1950s while prospecting for corundum for industrial use. The Zazafotsy rocks did not contain enough corundum to be worked for industrial corundum, and even though the crystals had a nice colour, they were not of gem quality.

After the discovery, locals and tourists occasionally collected corundum crystals weathered free from the host rock. Exploitation started here in 1989. In 2001 Federico Pezzotta and Rakotonoel (a Malagasy mineral enthusiast/dealer) managed to organize a more thorough excavation, and found two corundum bearing horizons.

The westernmost corundum-bearing lens is a medium-grained phlogopite/potassium feldspar/gneiss horizon with a thickness varying from 20 cm to 1,5 m with spinel, sillimanite and rhodolite in addition to corundum.

The Eastern location is a fine to coarse-grained feldspathic gneiss, with a thickness of 10 to 60 cm. Here the mineralization is less homogenous, with local concentrations of phlogopite bands and areas containing more or less rhodolite, corundum granules, and spinel with variable sillimanite content.

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.


Mineral List


6 valid minerals.

Detailed Mineral List:

'Biotite'
Formula: K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Corundum
Formula: Al2O3
Habit: elongated prismatic, normally simple hexagonal prism, but also complex combinations of pyramid, rhombohedron and small pinacoids,
Colour: red, blue, violet
Description: Western zone: The corundum occurs evenly distributed in the rock with no preferred orientation, and can be found in well developed crystals in various ruby red color tones, sized from 1 to 4 cm in size, averaging around 2,5cm. The crystals are generally elongated prismatic with a length and diameter ratio of from 2:1 to 3:1, but the crystal shape can be anything from a simple hexagonal prism to complex combinations of pyramid, rhombohedron and small pinacoids, and the crystal shape is randomly variable throughout this zone, and even crystals found near each other may have completely different crystal shapes. Eastern Zone: The corundum here is also more diverse, both in color and size. The crystals can be up to decimenter size and of various reddish, violtet and blue colors, sometimes completely enclosed of a potassium fedlspar halo (3-4mm-1cm thickness). Some of the crystals are also multicolored with shades of purple and red in the same crystal. Some of the larger multicolored crystals show a star-like feature with six scarlet arms pointing towards the centre of the prism face, with blue edges on the sectors between the "star arms". As a rarity, Pezzotta describes crystals to 2cm, with a remarkably intense blue color and high-gloss face, with adamantine luster, partially or totally enclosed in a casing of rhodolite garnet. Part of the face of these crystals are fully developed, but have developed in the competition with garnet creating complex growth structures
Corundum var. Ruby
Formula: Al2O3
Corundum var. Sapphire
Formula: Al2O3
'Garnet Group'
Formula: X3Z2(SiO4)3
'K Feldspar'
Magnetite
Formula: Fe2+Fe3+2O4
Muscovite
Formula: KAl2(AlSi3O10)(OH)2
References:
'Plagioclase'
Formula: (Na,Ca)[(Si,Al)AlSi2]O8
Sapphirine
Formula: Mg4(Mg3Al9)O4[Si3Al9O36]
Sillimanite
Formula: Al2(SiO4)O
Spinel
Formula: MgAl2O4

List of minerals arranged by Strunz 10th Edition classification

Group 4 - Oxides and Hydroxides
Spinel4.BB.05MgAl2O4
Magnetite4.BB.05Fe2+Fe3+2O4
Corundum4.CB.05Al2O3
var. Ruby4.CB.05Al2O3
var. Sapphire4.CB.05Al2O3
Group 9 - Silicates
Sillimanite9.AF.05Al2(SiO4)O
Sapphirine9.DH.45Mg4(Mg3Al9)O4[Si3Al9O36]
Muscovite9.EC.15KAl2(AlSi3O10)(OH)2
Unclassified
'Biotite'-K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
'Plagioclase'-(Na,Ca)[(Si,Al)AlSi2]O8
'K Feldspar'-
'Garnet Group'-X3Z2(SiO4)3

List of minerals for each chemical element

HHydrogen
H BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
H MuscoviteKAl2(AlSi3O10)(OH)2
OOxygen
O BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
O CorundumAl2O3
O MagnetiteFe2+Fe23+O4
O MuscoviteKAl2(AlSi3O10)(OH)2
O Corundum var. RubyAl2O3
O Corundum var. SapphireAl2O3
O SapphirineMg4(Mg3Al9)O4[Si3Al9O36]
O SillimaniteAl2(SiO4)O
O SpinelMgAl2O4
O Plagioclase(Na,Ca)[(Si,Al)AlSi2]O8
O Garnet GroupX3Z2(SiO4)3
FFluorine
F BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
NaSodium
Na Plagioclase(Na,Ca)[(Si,Al)AlSi2]O8
MgMagnesium
Mg BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Mg SapphirineMg4(Mg3Al9)O4[Si3Al9O36]
Mg SpinelMgAl2O4
AlAluminium
Al BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Al CorundumAl2O3
Al MuscoviteKAl2(AlSi3O10)(OH)2
Al Corundum var. RubyAl2O3
Al Corundum var. SapphireAl2O3
Al SapphirineMg4(Mg3Al9)O4[Si3Al9O36]
Al SillimaniteAl2(SiO4)O
Al SpinelMgAl2O4
Al Plagioclase(Na,Ca)[(Si,Al)AlSi2]O8
SiSilicon
Si BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Si MuscoviteKAl2(AlSi3O10)(OH)2
Si SapphirineMg4(Mg3Al9)O4[Si3Al9O36]
Si SillimaniteAl2(SiO4)O
Si Plagioclase(Na,Ca)[(Si,Al)AlSi2]O8
Si Garnet GroupX3Z2(SiO4)3
KPotassium
K BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
K MuscoviteKAl2(AlSi3O10)(OH)2
CaCalcium
Ca Plagioclase(Na,Ca)[(Si,Al)AlSi2]O8
TiTitanium
Ti BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
FeIron
Fe BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Fe MagnetiteFe2+Fe23+O4

Geochronology

Mineralization age: Cambrian : 494 ± 5 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic TimeRocks, Minerals and Events
Phanerozoic
 Paleozoic
  Cambrian
   Furongian
ⓘ Biotite494 ± 5 Ma

Other Regions, Features and Areas containing this locality

Madagascar
Somali PlateTectonic Plate

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

 
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