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

Photo Source : unknown

Giant Vivianite Crystals in the Anloua swamps, Cameroon

Coordinates : 7°25'N , 13°29'E : Anloua, N´gouandere, Cameroon

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Vivianite Crystals from Anloua, 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 soon 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 (now : MINES ParisTech) in Paris.

Large vivianite crystal specimen from Anloua
Collection Ecole de Mines (now : MINES ParisTech), Paris

Photo: Thomas Krassmann

The vivianite crystals of Anloua, which form stellate aggregates of more than 2 m diameter and individual crystals of a maximum size of 1,35 meter, are often somewhat rounded due to corrosive effect of humic acids (?) and display a greyish blue colour on surface. Only when backlit, they show their true magnficient bluish green 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 bogland enviroment.

In contrast to the above mentioned famous vivianite localities in Bolivia etc. the swamp vivianite rarely, if ever, form large crystals. However, this was the case in Anloua in Cameroon. Obviously there must have been a surplus of phosphate in the Anloua swamps, possibly derived from underlying phosphate rich rocks.

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 size.

Anloua Vivianite in a Nutshell :

Mineralogy :

Vivianite crystals in swamp environs

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 humic acid, oxygen poor millieu

Current status :


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) vivianite crystals 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, (now : MINES ParisTech) Paris

Photo : MINES ParisTech, 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


Vivianite crystal from Anloua on display
Natural History Museum, Calci, Pisa, Italy

Photo : Thomas Krassmann

Resources and relevant weblinks :

For more information on the mineral vivianite please look at, Webmineral and the german Mineralienatlas.

Surprisingly very little information is published about this famous and classic locality, at least not in english language. The collection of the Ecole de Mines, (now called MINES ParisTech) in 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 !.


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