(Esiva, Kaominina Maromby, Departementa Amboasary, Faritra Anosy, Faritany Toliary, Madagasikara)
The locality name "Esiva" refers to a pyroxenite vein that has been worked for thorianite and phlogopite. It is situated 5 km west of Andranondambo, which again is situated 20 km northeast of the small town Tranomaro in the southeastern part of Madagascar. The locality was first named "P.E. 1439 Hibon".
On the type locality of Hibonite:
Hibonite was first discovered by Paul Hibon in June 1953 in an alluvial deposit near Esiva ("en éluvion aux environs d'Esiva").
The largest Thorianite crystal from this location is 6 cm and weighs ca. 2.2 kg. Since 1962 it has the sample number "106222" (previously 6222) in the "Ecole des mines" in Paris. It was aquired by an Exchange.
Metamorphosed limestone, pyroxenite, gneiss, and granulite of the amphibolite to granulite facies.
References:
Delbos, L. (1955): Note sur le gisement d'un mineral nouveau " la hibonite" de' l'Androy Mandrareen" in Rapport Annuel du Service Geologique pour 1955, Tananarivo.
J. Behier (1960): Contribution a la mineralogie de Madagascar. Ann.Geol.de Mad. XXXIX. p 42-43
Besaire, H. (1966): Gites mineraux de Madagascar. Ann.Geol.Mad. XXXIV
Coordinates from: http://www.fallingrain.com/world/MA/6/Esiva.html
