[Rockhounds] fossils

[Axel Emmermann]

Hello blood brother,

> In line with the preceding paragraph, based on the new products
> available, we now have easy access to not only shortwave (~2537 Å) and
> longwave (~3510 Å), but "midrange" (~3120 Å) and "near-violet longwave"
> (~3680 Å).  This has opened up new information about what minerals fl.
> and under which region of light.  If you have all 4 of these lamp types
> available, you can determine much more about the minerals.

[Axel] I'd include 385 nm and 400 nm. Some hackmanite and ruby go berserk in
extreme long wave UV and blue light.


> 
> There is indeed an issue with how colors are described.  The dirty
> secret of Franklin material is that, while "red and green" rolls off the
> tongue and seems quite Christmasy, the fl. color of the calcite is
> actually orange-red.  The color of Mysore corundum is actually red, and
> in fact the spectrophotometer shows that is fluoresces into the near
> infrared.  

[Axel] Same activator (chromium) shows 5 magnificent peaks when incorporated
in spinel. It's awesome to see the spectra side by side.  To the human eye
there is no discernable difference. 

> 
> While I was typing this, another member sent a note talking about the
> MSH minerals.  I am moderately certain that the details of MSH
> fluorescence were the work of one man, the charming and enthusiastic
> Jacques Poulin.  

[Axel] Oh yes, Jacques... he's a real fluo-fundamentalist... Hail him ;-)))

We communicated on this issue several times in the last
> decade, and it took quite a bit of effort on his part to complete the
> task.  And that's the lesson: for a useful listing to be compiled, it
> takes the dedication of collectors who will gather the known minerals of
> a particular locality and catalog the fl. responses under 4 good lights
> emitting the aforementioned wavelengths.
> 
> I hope these random thoughts on the matter clarify some things.

[Axel]  I will agree on one thing ... fluorescence is a minefield ;-)))

Take care
Axel