Well, this is a real Tropen nib that's for sure and so far as I know Tropen did not get the nibs from Degussa.
It would be easy to type in "DEGUSSA" at google and you will find the "half- sun" emblem which is also the nib imprint. And you know nothing more about Tropen than you found in Lambrou`s FTOTW.
Wow! We are having a real flame war here on FPN. I never thought that would be possible!
So I might as well add my part for a few cents worth.
To begin with: I share Thomas' (aka Kaweco) argument that when a nib bears the famous 'halfsun' emblem, we are looking at a Degussa nib. Period.
Secondly: The history of a lot of German fountain pen manufacturers is poorly documented and is very difficult to access. A lot of history from the privat German industrial archives vanished or was destroyed during or shortly after WWII.
Fellow FPN member 'Kaweco' has an excellent reputation as an expert on German fountain pen history. In fact there are very few people I know in this small world of FP enthusiasts that know so much about the subject as he does.
In Andreas Lambrou's excellent reference work 'Fountain Pens Of The World' is a large chapter dedicated to the Tropen brand. This is in fact practically all we know and all we can find about the history of Tropen and the fountain pens they made. There may be more information, but it is not disclosed in databases or libraries and if its there it will probably be part of private archives and thus hardly accessible.
In the article in FPOTW the author indicates the interesting fact that Tropen was first of all a plastics manufacturer that produced plastic fountain pens already in the 1920's. Remarkable, in a time that mainly hard rubber and celluloid coming up, were the standard materials to make pens from. Gustav Schroeder, later Tropen, was a plastic manufacturer, certainly not a nib maker!
In Lambrou's book there are no pictures or descriptions of pre-war Tropen pens, let alone the nibs they used, so we cannot find any reference there.
Penandbyonds example of a white Tropen Ambassdor 800 is from 1958 and the 'PERLES' mystery pen I sold to Gobblecup is from somewhere between the late '30's and the 50's so I will concentrate on what we see about the 1950's pens in FPOTW.
Just like a lot of other pen manufacturers in Germany Tropen bought their nibs from 'third parties', some of them were well known, not in the least because of their high quality products. To name just a few: Bock, Rupp and yes, also Degussa.
In and after the war the use of gold was difficult or even impossible because the authorities had restrictions on the use of gold for FP's. So the Tropen no 500 Scholar, 1958 was still equipped with a steel nib. The Example in FPOTW show a 500 Scholar, as pen no. 2 on page 233. The nib is not shown, unfortunately. Yes, I own the book…
I also own some Tropens. Just 4.
One is the same as the no. 17 pictured on page 233 in FPOTW. A new no. 500 Scholar from 1989. Mint. Strangely enough it has an Ambassador GP steel M nib. Beautiful pen, I'm very proud of it.
One is a rare red Tropen Tiros, that does not have a regular nib but a sort of experimental ballpoint construction, that worked with normal ink. Not a stylograph nib or kuli, but different. But that will be something for another posting.
My other 2 Tropens are beaten old standard no.500 Scholar's made in the 1950's. One has a generic GP steel nib, probably a replacement, and the other has: YES! A Tropen nib! With a Tropen Logo. (see pictures).
When we go back to page 233 in FPOTW one can see only 5 pens of the 17 totally pictured that show the nib. The Photography and the printing is of excellent quality so when I take a magnifying glass to look at the details I see the nib of pen no. 7, (no.200 Splendid, 1954): a diamond with the half sun half moon logo. Degussa! Pen no. 9 (no.400 Mein Stoltz, 1964): Degussa! No 11 , a no.1200 with hooded nib. So also a hooded Brand…
Further, pen no. 13 on the page, a high end model Tropen no.3 from 1950 with a warranted 14K 585 nib with a Lion head's logo. I think that logo was used by Rupp. (Kaweco, correct me if I'm wrong). And the last visible nib on the page, pen no. 15 is the grey variety of Penandbyond's no. 800 Ambassador, with exactly the same two-tone Degussa branded nib.
What can we learn from this: Tropen indeed made (or had made) nibs with it's own logo. It is not a diamond form with a half sun in it. It is a shield form with the name TROPEN in it.
But on a lot of pens, from budget to hi end, Tropen used third party nibs, maybe mostly Degussa, but also other brands. As the pens that are shown in Lambrou's book all can be considered as mint or near mint, there is no reason to think that these pens were tampered with or had a replacement nib. I am absolutely sure that the pens as they are shown had these nibs when they left the factory.
So sometimes things are not always what they seem…. The German fountain pen industry has a very complicated but fascinating history. A lot still has to be researched. For most people this will be a trivial subject so in the big bad world practically no one is giving attention to this 'little history' But there is one thing I learned (among others) from this fascinating hobby: the fountain pen industry, the use, the makers and the users, the designers, inventors and the used materials, from, say 1875, to today reflect what happened then and happens today in this world. History at it's best!
Another thing you can learn, reading the postings and articles on this great FPN board that it is a great thing that members are willing and able to share and evaluate their expertise on the subject. I think it is essential all board members show respect for that.