Thread: Purple Slurry = Blue Belgian ???

Originally Posted by Chrisl

Old_School recently cut up a natural combo into slurry stones.

And I bought one. It's in the mail. =)

You my friend, have totally scored! Nice combo stone! You'll be very very happy with it...in the pics it looks to me like you have a non-natural combo; these have not been produced for IIRC 50+ years?

Yep. It's glued. A non-natural combo, but a combo nonetheless.

Thanks, everyone. =)

Me

Slate makes a dark gray slurry and the blue makes a purple slurry. That property is called "streak" to geologists and is one of the field tests used to identify stones. They rub the stone against a little pad of sand paper or a ceramic plate and the true color comes out and that's the "streak".

Howard

Ardennes Coticule uses slate to back their coticules, but the old coticule producers used Belgian Blue stone. After all it was plenty available. Ardennes doesn't do that anymore, because it is much more cost-effective to glue to, foreign produced, slate flooring tiles. (Labor costs have exploded since the old days). Anyway, almost all vintage coticules are glued to a blue stone, while Ardennes' coticules are backed to slate, unless they don't need to glue it, in the case the blue is naturally bonded to the yellow.

Bart.