Looking at a job.  I haven’t worked out whether the wall is structural yet.  But the bricks are weird.  They are aprox. 12″ long X 6″ high.  They are made of a very porous looking red clay (so many small air bubbles/holes they look volcanic) and have a couple of  1/2″ wide smooth score marks running the length.  It’s an interior wall separating apartments, and was previously covered with plaster etc..

I’m curious as to the history etc  of this kind of brick, as well as it’s properties.  Thanks to all, Patrick.