okay, trying the photos again, I think these are better
I know exactly what you mean Floor, but I don't think they're block turquoise, to me block turquoise feels almost waxy and is comparatively light weight versus these beads, and they're colder to the touch than resin. It's so hard to get across in photos, wish you could feel them!

I'm almost certain they're either glass or a heavy porcelain with a really deep and intricate glaze. If you look around the holes you'll see some damage, the edges are crystalline like glass. The pattern of the brown areas is very wispy, like the center of some Venetian murine, I think they've been called bifurcated murine or something like that. Could they be a Venetian attempt at faux turquoise?

they may just end up being (dun dun duuuuuh) Mystery Beads! :)