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PhotosDravite - Lelatema Mts, Simanjiro District, Manyara Region, Tanzania

24th Apr 2014 14:56 UTCEric Greene

Dravite, Rutile

Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania

In Tucson I bought several color change crystals from Leonard Hines that exhibit a color change from dark green when front lit to reddish orange when back lit. This appears to be what is called the Usambara color change. The locality on the Hines label is Mwajanga, near Komola, Tanzania. After further research, these crystals look similar to material that is attributed to several other localities:

Mindfind gives the locality as Numalulu Tanzania Dravite (see http://www.minfind.com/mineral-168333.html)

The Mindat page for dravite from Tanzania, does not list Numalulu or Mwajanga, but has one specimen from Lelatema Mts, Simanjiro District, Manyara Region, Tanzania showing the color change effect. (see http://www.mindat.org/gallery..php?cform_is_valid=1&loc=4384&phototype=1&cf_pager_page=9)

And, Marin Minerals gives the locality for Usambara color change as Nchongo, Umba Valley, Tanzania (see http://www.marinmineral.com/usam.html)

Also, on the Marin page there is a link to another website which gives Nchongo as the locality and has a detailed discussion of the color change (see http://www.nordskip.com/usambara.html)

It is not uncommon for material to be attributed to several localities when dealers are trying to hide the true locality (remember the problems with the early Chinese material?).

Can anyone help sort this out?

30th Oct 2014 17:12 UTCfaber

Dear Eric,

Dravite are common in many tanzanian locality, but about the change color dravite I never seen in landanai or mwajianga, more probably they came from umba valley (tanga region).

Many peoples confused this locality (may be to mainteins the secret o because they don't know the region) but you know that only in landanay are several dozen of turmalines mines, like in silimanjiro dst. (mwajianga, lemshuko ecc) and are several hills that produced different turmaline specimens. Sometime the turmaline change also in a same "shimu" (in swahili hole). I observed many samples from tanzania, but I'm shure that specimens you posted do not came from mwajianga o lemshuko o landanai (in maasai steppe) were more turmaline have a cromium inside (green turmaline that local people call "Kombat").

many people have a confused "map" of tanzania mineral localityes but often also the local dealers do not have any idea about were came from some specimens! And more most of the specimens came without matrix so is very hard to make a goal in many cases.

regard

Fabio

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