Maybe the summer is the time for bright, vibrant colors... but recently I am more drawn to dark brown colors like yama-guri. This interest also made me buy Macassar. And this color has not disappointed me. A very dark brown, leaning towards black. A pleasant color to take work notes, easy to read. But, definitely suitable for personal correspondence and writing as well. As always, depending on the subject and mood of course.
Diamine inks are smooth, a bit wet and well-behaved. Macassar is no exception. No feathering, a nice shading and negligible show-through. Water resistance is low (and turns the remaining brown into orange) and drying times are a bit above average, 40 seconds on Rhodia paper. Personally I prefer wetter, broader nibs for these colors. But that is personal taste, the ink behaves equally well in fine and extra fine nibs.
Compared to yama-guri the color is quite similar. Yama-guri is even darker. Cacao du Brésil (Herbin) and even more so Caroube the Chypre (Herbin 1670) are significantly lighter.