Platinum Carbon & Pigment Inks (4-Pack)

I thought the huge shipping cost must have been a mistake, so I've been waiting for it to be corrected, but maybe this it it? I know international shipping is not easy for massdrop, but some explanation in cases like this would make me trust their system a bit more.

Platinum are a very well respected (Japanese) maker of fountain pens. These pigmented inks are specifically designed for fountain pens. While you are correct that most pigmented inks - particularly the old fashioned india ink type inks - are completely incompatible with fountain pens, the new nano-tech pigmented inks such as these and those made by Sailor (Japan) and De Atramentis (Germany) are safe (if maybe a little more high maintenance than say Waterman Blue). While I wouldn't leave a pigmented ink in a pen for 6+ months, leaving it to dry out etc, I've never had any problems leaving the Sailor nan-ink in a pen for several months. EDIT - for more information (including reviews) about these inks check out the fountainpennetwork.com fora.

The description mentions it, but generally, all fountain pens cannot take pigment ink. Pigments are solids floating in the liquid. Solid particles + fountain pen = clogged pen. It says these are ultra-fine pigments, which may be friendlier, but if anyone's buying these to use in a fountain pen, I would recommend triple-checking with others.