© 1998 by Udo J.A. Behner
© 1998 by Udo J.A. Behner
e.g. ammonium magnesium sulfate doped with cobalt
| chemical formula | : (NH4)2(Mg, Co)(SO4)2 · 6 H2O |
| crystal class | : monoclinic prismatic |
| growing method | : slowly cooling of the aquaeous solution |
| growing time | : app. 7 days |
| crystal size | : up to 5 centimeters |
This is a huge specimen of so called ammonium cobalt sulfate
but however this is only cobalt doped ammonium magnesium sulfate.
Its an example of the Tuttons Salts which have the general
formula X2Y(ZO4)2 · 6 H2O
where X represents either K(Potassium), Rb(Rubidium),
Cs(Caesium), Tl(Thallium(I)) or NH4(Ammonium) and
Y can be Mg(Magnesium), Zn(Zink), Mn(Manganese(II)),
Cu(Copper(II)), Ni(Nickel(II)), Co(Cobalt(I)), Fe(Iron(II)),
Cd(Cadmium), Cr(Chromium(II)!) and V(Vanadium(II)!).
The anion ZO4 may be represented by SO4(Sulfate),
SeO4(Selenate) or CrO4(Chromate).
Its supposed that they can form mixed crystals all together so
far as they are chemical compatible.
I have also been growing pure ammonium cobalt sulfate which is
dark red in color with a little brownish to purple hue, but due
to the high price of cobalt I use this expensive ingridient only
as a "dye" to get various color shades of pink and red
in ammonium magnesium sulfate.
This specimen is currently exhibited at the mineral museum in
Pforzheim.