© 1998 by Udo J.A. Behner
© 1998 by Udo J.A. Behner
colored with methylene blue
| chemical formula | : KAl(SO4)2 · 12 H2O |
| crystal class | : cubic disdodekaedric |
| growing method | : slowly cooling of the aquaeous solution |
| growing time | : about 72 hours |
| crystal size | : app. 4 to 5 centimeters |
In times there was not such a variety of colorfull salts
available for me, I tried to produce potassium alum in various
color shades simply by adding water soluble organic dyestuffs to
the solution.
The result is mostly a mechanical inclusion of the colored
solution in the crystals which also uses to fade when the
crystals dries out.
However some dyestuffs are also adsorbed on the crystals surface
and "built in" so you get a more real coloring effect.
This specimen is currently exhibited at the mineral museum in
Pforzheim.