So, I think a fair amount of people own a Jinhao pen, the 750 mostly (pictured above), and I think most people have noticed that most nibs have "18KGP" stamped on them. The explanation
I've heard is that this might be because they stamp all their nibs and only gold plate some. Well... let's all put on our Sherlock Holmes deerstalker hats and grab the nearest meerschaum pipe to investigate.
The first thing you might say is 'well, isn't gold... gold colored'? And the simple answer is: not always. Gold we handle is usually always in alloys, and the cheapest metal to mix with gold to make
it strong enough for daily wear-and-tear is nickel, which can turn gold a silver color (or the term 'white gold' is used).
The nib in question:
I just happen to have a gold testing kit lying around, consisting of various grades of nitric acid. The idea is, say if I used the 14k nitric solution on any grade of gold below 14k gold, the acid
would react with the gold and eat at it.
The plan was to rub the nib on a stone and test the metal that came off with the 18k and 22k rated acids. I also rubbed on a sample of gold, (probably low 22k, maybe 21k) for comparison.
The gold has the 22k solution of acid on it, and you can clearly see it is being eaten. The top left is where the nib was rubbed, and it is holding fine up the 18k solution. Now, just the fact that
it rubbed off anything is a good sign considering the stone isn't very tough (gold is fairly soft, even in alloy form) and steel probably wouldn't rub off on it that clearly.
Here is where I tried again, but put the sample under the 22k solution and you can definitely see that it has reacted (I left some untouched to the right).
Now, stainless steel is usually resistant to nitric acid in most concentrations (in fact it's usually the metal to use when dealing with the acid), but not all stainless steels are equal and I
imagine Jinhao is not known for high grade steel. It could just be a coincidence that the metal reacted with the 22 and not the 18, but that would be some coincidence.
This is neither a definitive nor completely scientific test and I'm still not 100 percent sure either way so use this information how you will.
And if you're worried, no nibs were harmed in the making of this post. The nib was explained the risks and of his rights before the experiment started.
Edited by Maer, 19 July 2012 - 19:10.