@ henk
Interesting cataloque! The Schleifmittel AG was founded 1923 out of the Escher & Co, Bösenberg & Trinks, Pike & Escher and some other companies. They and the JGES company which was founded out of the Escher & Son company also sold thuringian bouts (Brocken) in analogy to the coticule bouts. Means stones of different shapes, which could not be cut as bench stones. Bouts were sold from ordovician and also the devonion stones. I got a lot of two colored (Yellow-green/Blue "Barbers deligth") waterwhetstone bouts which have triangle and other shape. So it is not clear to me which stones are meant here. Do you have a better copy of this cataloque side?
Since the mine that we talk about was closed 1923, the cataloque may not deal with the aforementioned stones.

The stones showed in the slate museum of Ludwigstadt are all from the different ordovician quarries in the Bavarian/Frankonian area. I have visited the quarries about two years ago. This will be handled in a separate thread (ordovician part 3) - if of interest for the members here.

@MuskieMann33
Yes this is definately an Escher labeled stone. Not only the cup, below the cup you can also read: "Marke E&Co" = brand Escher&Co. The man with knife in the hand on the other side of the logo was the trade mark of Bösenberg&Trinks.
So that is interesting. Bösenberg&Trinks Company (BTC) rented the quarry from about 1870 on. Escher&Co stilll existed at this time. The companies were owned by different kins of the Escher family.
I think the stone was mined after 1870 by BTC. But the stones had become famous under the trademark Escher&Co. So BTC stated on the label brand E&Co and the well know Escher cup beside their own trademark (most probably with acceptance of Escher&Co).

@ doorsch
I think the above explain the item. The Schleifmittel AG used this logo (which they took over from BTC) until after WW2.