Black Forest Pens Rhombus Fountain Pen - Grey Anodised Aluminium

The Rhombus fountain pen is machined from anodized aluminum and features a barrel covered in precisely milled diamond-shaped facets. Each geometric surface is cut directly into the metal, creating a tactile grip pattern that also catches light from multiple angles. The result is a pen that feels secure during long writing sessions while looking like an engineered object rather than a decorative one.

The body is made entirely of aluminum, then anodized in a matte grey finish that resists wear and hides fingerprints. The milling process removes material in a repeating pattern, leaving raised edges and recessed valleys across the entire grip section. This texture provides friction without sharp corners, so the pen stays put whether your hand is dry or slightly damp.

A #5 steel nib handles the writing work. You can choose between fine or medium line widths depending on whether you write small or prefer bolder strokes. The nib is a standard size, which means replacements and upgrades are straightforward if you want to experiment later. The pen posts securely and writes with the cap off, keeping the balance point near the middle of the barrel.

Black Forest Pens manufactures this in Germany. The threading is clean, the cap seats with a single turn, and the converter or cartridge fits without wiggle. The grey anodized surface is uniform across the body and cap, with no color variation or unfinished edges. The geometric milling is consistent from end to end, with each facet meeting the next at the same angle and depth.

This pen weighs enough to feel substantial but not so much that your hand tires after a page. The aluminum construction keeps it lighter than brass or steel alternatives while still offering the cool, solid feel of metal. The matte finish and machined texture give it an industrial look—no ornamentation, no branding on the barrel, just the rhombus pattern and the shape of the pen itself.