GR translation: wet pools of Prussian blue

[David Morris]

http://en.wikipedia.org/wiki/Prussian_blue_(color)

Prussian blue is a dark blue pigment with the idealized formula
Fe7(CN)18 Another name for the color Prussian blue is Berlin blue or,
in painting, Parisian blue. Turnbull's blue is the same substance but
is made from different reagents. It is employed as a very fine
colloidal dispersion, as the compound itself is not soluble in water.

Prussian blue is one of the first synthetic pigments. It is famously
complex,[1] owing to the presence of variable amounts of other ions
and the sensitive dependence of its appearance on the size of the
colloidal particles formed when it is made. The pigment is used in
paints, and it is the traditional "blue" in blueprints. It has been
used as an antidote for certain kinds of heavy metal poisoning
(caesium and thallium).