I have received these 2 hones a few weeks ago from the workshop of an older gentleman from mid-80 (he collects and restores tractors). He got it again about 50-60 years ago from the workshop of a carpenter from Thuringia. I therefore estimate the hones date from before WW II.
*The first hone is quite clear. It is, in my opinion, a Thuringian slate. Size 130 X 40 mm, weight 270g. Smooth surface, medium hard, easy to use. It brings excellent, mild sharpness. Any sugestions?