I happened to have a sample of Faber-Castell Garnet Red, which I have been using in a Kaweco AL-Sport with fine nib. Garnet Red is a nice burgundy color, and it comes close to what I think of as the birth stone’s color.
Lighting makes a huge difference with this ink. These photos were shot on a bright sunny day (after a snowfall), and the red is strong. But in dimmer or overcast light, the ink has a browner tint.
Faber-Castell Garnet Red is an ink with lovely lubrication and flow. Writing with it feels positively luxurious, even with a steel nib pen. Although the ink has no flow problems, I do think the color of Garnet Red benefits from a wet pen, like the Kaweco AL-Sport I used.
When I compare Faber-Castell Garnet Red to other inks, it is closest to Montblanc Burgundy Red and Monteverde Burgundy. (I mention both Montblanc and Monteverde because, as discussed here, those two inks look nearly identical to each other.)
You can see that Faber-Castell Garnet Red is darker and deeper, and has a browner tint than the Montblanc/Monteverde ink. Garnet Red also has more body to it and much more presence on the page.
I compared paper towel chromatography results, which shows the same thing from a different perspective. From left to right, the chromatography tests are of Faber-Castell Garnet Red, Montblanc Burgundy Red and Monteverde Burgundy.
However, while it’s darker than the Montblanc/Monteverde ink, Faber-Castell Garnet Red is not super saturated or dark. Here it is compared to two Diamines. Garnet Red is less saturated and comes across as cooler in color than either Diamine Burgundy Rose (which is similar to Montblanc Hitchcock) or Diamine Oxblood.
You can see that Burgundy Rose, like Hitchcock, is more cheery (and slightly more pink) than Garnet Red, while Oxblood is browner than Garnet Red.
I think Faber-Castell created a lovely, complex ink here. When it comes to this particular hue, my heart belongs to Montblanc Alfred Hitchcock (or Diamine Burgundy Rose when the Hitchcock runs out). But Garnet Red is another great option, as a burgundy that’s just a little bit cooler and a little bit browner. Also, it really makes me think of red wine.