'Iridium point Germany' is a meaningless phrase.
Iridium is a very hard metal that was used in tipping fountain pen nibs many years ago. Pure iridium is rarely used at tipping material today.
There are two theories to explain the term 'iridium point Germany'. One is that 'iridium' is a generic term for tipping metal, and the phrase indicates that the metal was purchased from a German supplier.
The other theory is that the term only means that the nib was manufactured using technology that originated in Germany. Prior to the advent of ball-point pens, there were a number of very good manufacturers of fountain pen nibs in Germany. When ball points displaced the market, many of those companies went out of business, and sold their manufacturing equipment to the upstart markets in Asia. So it became common for Asian pen manufacturers to label their nibs 'iridium point Germany' because they were made on German machinery.
Both interpretations can be categorized as 'marketing hype' and therefore meaningless.
As to nib width - there is no industry standard defining terms like 'fine', 'medium' or 'broad' - each manufacturer applies whatever label he chooses. That said, nibs originating in Asia tend to be narrower than nibs with the same generic label originating in Europe.
Chinese pens tend to have relatively fine nibs. Pen kits tend to come with nibs that are a bit broader than Chinese pens, but not as broad as European 'medium' nibs. Ed provided the link to Richard Binder's stroke sample chart which helps visualize nib width. Ultimately, it comes down to the individual user trying various pens and choosing one that writes to his satisfaction.
