Belgia Brocken, Information on Schleifmittel Akiengesellschaft Sonneberg (SAG)

Here are some shots from a newsynthethic Cotcule i got last week. After checking several sources iam quitesure that this is a "BelgiaBrocken". Those were also sold from SchleifmittelAktiengesellschaft (SAG) in Sonneberg.

The "BelgiaBrocken" were synththic made stones which were announcedas a substitute for the Belgian Stones. They appeared in a Coticule styleVersion with a darker/black backing and that Coticule style top. The othervariant beeing sold was a complete "Coticule only" stone which wassold in sizes. 5 1/2, 6 1/2, 7 1/2, 8 1/2inch.

Here is the extract from that catalogue page from the Pricelist ofSchleifmittel Aktiengesellschaft from 1930.
https://c1.staticflickr.com/9/8537/2...6efec5_c_d.jpg

The stone seems very fine and actually it can be compared with the reformThuringian stones. This material is much harder but it has the same synthethicsmell so iam sure that some parts of the incredience might have been the same.Unclear is if SAG really made this stone or if it is probably a JGES or Apexstone. It could be that both JGES and Apex produced comparable stones. Unclearis if they use coti dust on those, because they sold these as"synthethic" stones.

there is no additional marking existent, so the producer/supplier can't beconfirmed.
This one only shows the quality stamp "extra-extra" and"No.8".

https://c1.staticflickr.com/9/8802/2...b9d2b5_c_d.jpg
https://c1.staticflickr.com/9/8676/2...949c76_c_d.jpg
https://c1.staticflickr.com/9/8510/2...18a270_c_d.jpg
https://c1.staticflickr.com/9/8433/2...e21d57_c_d.jpg