Excelsior

I am trying to find out which tool enhances/adds which abilities to armor or weapons compared to normal ones of that type. or is it totally random?

Here's what you get from different resources: http://www.uoex.net/wiki/Resource_Properties

Runic tools add a chance for more attributes on a crafted piece, it's semi-random on jewelry as far as i know. There's a post here somewhere with some data on the subject.

Some crafter could give a more detailed answer