Historic photo : Excavating giant vivianite
crystals by local miners in the Anloua swamps

Photo : historic, source unknown

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Vivianite - Vivianit - Vivianite - Vivianita Africa : Cameroon : Vivianite crystals up to 1,35 m size in the Anloua swamps Coordinates : 7°25'N , 13°29'E : Anloua, N´gouandere, Cameroon

There are some localities in the world, which have supplied large and often beautiful crystals of Vivianite : Llallagua in Bolivia is one of them, Cornwall and Kertsch on the Krim peninsula are others, but Anloua in Cameroon supplied the largest by far. The vivianite crystals in Anloua were discovered by chance by some local farmers around 1920, but were later systematically excavated under french colonial supervision (see image above). Indeed this operation managed to obtain some very large and almost undamaged vivianite crystals, which are ever since on display in the famous Ecole de Mines in Paris. The vivianite crystals of Anloua, which form stellate aggregates of more than 2 m diameter and individual crystals of a maximum of 1,35 m, are often somewhat rounded (due to corrosive effect of humic acids ?) and display a greyish blue colour. Vivianite is a very common mineral in swamps and many localities are known - in fact most of the swamps in middle Europe - where this iron phosphate forms white earthy masses and crusts, which rapidly turn bright blue when exposed to fresh air. This is the so called "Blaueisenerz" (blue iron ore) which forms by interaction of iron and phosphorous rich solutions in an acidic, oxygen poor hydro-enviroment. In contrast to the above mentioned famous vivianite localities in Bolivia etc. the swamp vivianite rarely, if ever, form crystals. However, that was the case in Anloua in Cameroon. The question remains, why... Even if the giant vivianite crystal finds of Anloua seems to be long gone history, the locality still produces vivianite specimen, which can be found from time to time on mineral fairs, mostly in form of thin, bladelike translucent cleavage fragments up to about 40 cm.     The Anloua vivianite in a nutshell : Mineralogy : Vivianite Crystal Size : prismatic crystals up to 1,35 m and "crystal stars" to 4,5 m size Geology & Formation Recent to subrecent In situ crystallisation in peat / swamp environs from iron and phosphorous rich solutions in acidic, oxygen poor millieu Current status : unknown Remarks : A classic site of giant crystals, which apparently still produce vivianite specimen from time to time       Other notable & famous vivianite occurences : - Splendid groups of crystals up to several cm at the iron mines of Kertsch, Crimea peninsula. - Common in crystals up to 30 cm in various bolivean sulphide deposits, namely Morococala, Huanuni and Llalagua and others. - Crystals up to 12 cm are known to occur at the Trepca polymetallic sulphide deposits, Kosovo - Serbia - Equally large (12 cm) came from the San Antonio Mine, Chihuahua, Mexiko - A most unusual find are semifossil elephant tusks and other bones, completely or partially replaced by vivianite in several countries of tropical Africa.

Specimen of Anloua vivianite on display in the Ecole de Mines, Paris Photo : Ecole de Mines, Paris   Detail of a vivianite crystal from Anloua Collection : Fersman Museum, Russia Photo : A.A.Ebseeb   Famous mineralogist Claude Guillemin among Anloua vivianite crystals Photo : unknown, ca. 1960     Resources and relevant weblinks : For more information on the mineral vivianite please look at www.mindat.org, Webmineral and the german Mineralienatlas.   Surprisingly very little information is published about this famous and classic locality, at least not in english language. The Ecole de Mines, Paris displays some magnificient crystal clusters and single vivianite crystals from this locality. Further more, the Museum of the B.R.G.M at Orleans shows a part of a truly giant vivianite rosette, originally measuring 4,5 m in diameter !. Another image of a large vivianite crystal, photographed by us in the Natural History Museum, Calci, Pisa, Italy, can be seen here