This seller is selling his stones for years, it's the first time I'm aware of that he used the words Welsh and thuringian together. Most of his other stones are named welsh slate or something like that. In the hone selling business, slate hone doesn't mean it's actually slate. It never does (shale are most of the "slate" hones we use). Also, there would definitely be slate quarries in the thuringian region. Thuringian slate doesn't mean Thuringian celebrated hone.