Without a clear brand mark, identification is possible from the nib, the clip, the section and the barrel end; close-up photos of these areas help. A small, partially hidden nib points for instance to a Parker or a French make, while a blind cap at the barrel end qualifies that. Repairing a broken nib is very expensive; it is usually cheaper and more sensible to find an intact original nib of the same model and fit it. A list of repair specialists is on fountainpen.de; for nib-only work nibs.com is an address. With pre-war pens the feed and nib can often be carefully pulled out from the front. Markings like "14K"/"585" on the nib confirm gold quality; concrete dimensions help the repairer find suitable replacement nibs.