Silver is a rare spawn from Tin nodes.
Gold is a rare spawn from Iron nodes.
Truesilver is a rare spawn from Mithril nodes.
Eternium is a rare drop from all Outland veins.
Khorium is a rare spawn from all Outland veins.
Saronite and Titanium share spawn points.
So, basically, if one node type, which is rare, potentially spawns at the location of a known base node, putting the rare spawn node icon there would be misleading. If you're searching only for the rare spawned node, you're just going to have to check the base node locations to find the rare.
after pondering a bit i came to the same conclusion thx for confirming my train of thought. Not to nitpick, but i think eternium never spawns on it's own, it is kind of a rare bonus from Outland nodes. Great job all in all Jeffy, with the troubleshooting