I am slowly working my way through City Series pens. The latest in use is the beautiful Madrid model - fiery transparent red with black marbled finish. The black does turn slightly silver at certain angles to a light source.
Do the tines look aligned to you? This 18K gold version of a M600 nib is a wet writer and works pretty well with the De Atramentis ink.
De Atramentis inks come in cute little 35ml bottles.
Terra Di Sienna (Sienna earth) is pretty nice shade of brown. I really like this shade, it is especially nice on cream coloured paper.