Coticules and the spessartine garnets can be found on many places all over the world. One can spend days reading on the Internet about them. About how spessartine Garnets were first found in Germany (in sizes big enough for use as gems), (Spessartine: Spessartine mineral information and data.)
They can be found in magmatic, metamorphic and pegmatitic rocks. They're only called "Coticule" when found in a metamorfic schiste. There are many known finding spots.
But I've never found a direct source about Coticule being actually mined and used as a honing stone, outside the Vielsalm area, Belgium. That doesn't mean it's not possible. Just that I haven't found any sources testifying about it. To complicate matters, Belgian Coticule has been exported by various companies all over the world, often re-branded, by companies outside Belgium. "Pike" is a know example of a company doing it.
To complicate further, Belgium only exists since 1830, with borderlines discussion going on for another decade.
After WWI, as pointed out earlier in this thread, a part of Germany was add to Belgium. But Coticule extraction in this region started with certainty before 1548, the date of a known document that mentions commercial Coticule activity.
During the following centuries, the reputation of the hones was outstanding enough for many competitors of other rock to make all kinds of referrals and claims.
A source exist from 1776, testifying about the export of over 100.000 hones annually, to all European countries, parts of Asia and the American colonies. A long list of mine owners and companies exists from these times till the present date.
But not one source I've read mentions any foreign competition. One geologist I spoke to about a year ago, told me about a Scottish finding spot of Coticule, of some geological meaning, but that rock is neither pure nor cohesive enough to be suitable for hones.
I have also read one source mentioning that the ancient Romans used Coticule rocks they harvested at the river "Tmolus", completely unknown in our days, but likely situated in the West of Turkey.
To close this post:
If you search Google Maps for "Coticule", you'll find a lot of Belgian places, but also one spot in Germany, very near Ratisbon (Regensburg), our most cited source for "German" Coticule. The actual spot happens to be the home of Steffen J. Lindner, who owns the Internet domain names of Belgischer Brocken, a well-know reseller of Coticule (with excellent reputation). His little marker on the map says "Piedra de Afilar Belga natural - Coticule en venta en eBay". Is it possible that someone mistakingly read this as if Coticules are also mined at that part of the world?
Kind regards,
Bart.