Well, I've to steal some off your glory there. It's far from the oldest. You're on a mad competition course with Denmark (Greenland), Canada, Russia, South Africa and Australia, among others.

The oldest gneisses I know of are visible at an outcrop beside the main motorway leading out of Mbabane in Swaziland. But time moves fast; perhaps they identified an older one by now...

But Pre-Cambrium, you bet your pants. Stable as... as... well, a rock. At the structural geology group in Utrecht, they work mostly in Norway, but also Lapland is in the spotlight. There's an interesting new tectonic phenomena developed by the group based on what they pry out of the rocks in Scandinavia from the Caledonian Orogeny: dunk tectonics they call it. It has been causing somewhat of a stir among the structural crowd as it upsets the idea that the process of subduction and getting rid of crustal material is far too simple a model.

Baltica was a big orogeny player in geologic history: Here's a snapshot of what they think the globe looked some 400 plus million years ago. Spot your beloved Finland...