[Rockhounds] AD- Connrox Minerals

[Axel Emmermann]

[Axel] Hi Pete
 
> Axel, since I know you're interested in this, the latest (March) issue of
> Mineral News has an article by Van King tabulating the fluorescence of
> tourmalines from as many worldwide localities as he was able to examine.

[Axel] Yes, he (and his colleagues asked for some photos of fluorescent
minerals in both daylight and UV in the same orientation. I don't know if
they used them or not. 

>   He
> lists three and a half pages of observations; I'd say that somewhat less
than
> half of the specimens showed some kind of fluorescence, and only a few
were
>  described as "bright".

[Axel]  I would describe the Brazilian tourmalines as medium strong or just
below that. I have a few large pieces. Color has much to do with it
apparently! The really pink ones from Afganistan are nearly as bright as
benitoite under UV.
I'm not sure but it could be the same activator too. Titanium, if I
corrember remectly.
 Some of the Brazilian tourmalines have a brownish tint. Iron slightly
quenching?
I just NINGed them ....  so go have a look.

I just bought a small dravite X ... from the Nchongo Area, Umba Valley,
Tanzania. It not only fluoresces weak yellow, it also shows the Usambara
effect.  

Cheers
Axel