The edition consists of turned grenadilla, a nearly black South American precious hardwood also used in instrument-making (e.g. saxophone mouthpieces); clip, blind cap, cap top and fittings are of 925 sterling silver, in the 4810 variant with wood inlays, in the 888 variant with onyx. The bicolour nib with the sextant motif is described as particularly successful in design; the pen lies massively and heavily in the hand due to wood and silver and writes softly with the M nib. Grenadilla, like ebony, is heavier than water but, due to higher oil content, more pliable and so less prone to cracks, so normal use should generally not harm the material. On the wood's light sensitivity no firm statements exist; slight patina marks on silver through skin contact, by contrast, are usual.
Related pages on fountainpen.de:
• Patron of Arts Alexander von Humboldt: https://www.fountainpen.de/patron-humboldt-en.htm