Ilakaka gem deposit, Ilakaka Commune, Ihosy District, Horombe Region, Fianarantsoa Province, Madagascar
|Latitude & Longitude (WGS84):||22° 41' 53'' South , 45° 13' 4'' East|
|Latitude & Longitude (decimal):||-22.69806,45.21778|
|Köppen climate type:||Cfa : Humid subtropical climate|
An alluvial gem gravel deposit discovered 1998. One of the largest sapphire deposits in the world. It is located Close to the route national 7 going to Tulear, in the Horombe region in the southwestern part of Madagascar.
A large number of new gem deposits of the same character has also been discovered in the area around Ilakaka and further southwest in the Sakaraha area (see http://www.mindat.org/loc-45924.html). There is also a third district near Bezaha close to the Onillahy River 118 km southwest of Ilakaka.(see http://www.mindat.org/loc-217183.html)
NOTE: the name "Ilakaka" in the litterature refers not only to the Ilakaka deposit, but also sometimes to the whole gem deposit area.
10 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
201.3 - 252.17 Ma
|Triassic sedimentary rocks|
Schmetzer, K., Glas, M. & Bernhardt, H-J. (2002): Sterngranate aus Madagaskar. Lapis 27 (2), 20-27
Hogg, Jonny (2007): Madagascar's sapphire rush. BBC News, 17 November 2007.
Giuliani, G., Fallick, A., Rakotondrazafy, M., Ohnenstetter, D., Andriamamonjy, A., Ralantoarison, T., Rakotosamizanany, S., Razanatseheno, M., Offant, Y., Garnier, V., Dunaigre, C., Schwarz, D., Mercier, A., Ratrimo, V., and Ralison, B. (2007): Oxygen isotope systematics of gem corundum deposits in Madagascar: relevance for their geological origin. Mineralium Deposita 42, 251-270.