The hue of this ink is unlike anything else in my (kinda huge) collection. It's a gray-brown ink that tends to shade from one to the other as you write. Here are a few examples.
It's dark enough to be formal-ish, but no one is going to think that you're using a boring ballpoint when you use Cacao du Bresil.
This is one of my favorite inks. I've only tried a few J. Herbin inks, and I've rarely been disappointed. I'm not 100% sure that I would have bought this one for myself, but my wife got me a bunch of samples for xmas, and this was one of them. I tried it first because I'd never heard of it, and it has been in that pen ever since. I'll certainly be getting a bottle of this stuff at the next pen show.
I have no idea how to say the name of this ink. I assume that there's a French pronunciation for these words, but I don't know it. Anyway, you'll get to hear me butcher it in the video below.