Rohrer & Klingner Writing Ink - 50 ml Bottle - Smaragdgrün (Viridian Green)

I absolutely adore the color of this ink, but I'm worried it might be doing bad things to my pen.

After having the ink in my pen for a few weeks, I've noticed weird crystal things growing on the underside of the feed and nib. If that's going on on the outside of the pen, what might be happening internally? It does seem to be clogging up, and this is a pen that hardly ever clogs. I've never seen crystallization like this from any other ink I've used.

The color, as other reviewers have stated, is really amazing and has the most shading of almost any ink I've used. I would love to continue using it, but at this point I'm too concerned to put it in any pen that cost more than about five dollars.

R&K's "Verdigrease" is an intense, luscious color that flows smoothly and looks great on Clairefontaine paper. It is one of my favorite inks produced by this venerable German ink manufacturer.

I don't favor green inks at all, but this is my ALL TIME FAVORITE. It's a must have. It's like having two inks in one. Each line drawn with this ink has a lot of shading to it. It has character. Simply marvelous.

This is one of the most incredible fountain pen inks ever. Its like having two colors in one -- that's how much shading there is to it. I don't even favor green ink, but this is the best of all inks. I highly recommend it.

It'll grow on you like a fungus... :-)

When I initially tried this, it was honestly just so I'd have the chance to say, "Wow, what a hideous ink!" But, the longer I used it, the more and more it grew on me. Two years (and at least 2 bottles) later, it's earned a permanent spot in my rotation, and it's become a favorite! Like others have commented, it's got terrific shading properties, and it's pretty well-behaved (which, in my case as a lefty overwriter, is a must)! It's got a mild-enough formula that it's safe to use with vintage pens, too. I've got it loaded in a Sheaffer's PFM II right now!