These are all hand-made, unique pieces - so there is a lot of variation between them. Some of them only have "facetted" sides which have been flattened on the marver - but then not subsequently polished.
These were considered to be "serious art works" rather than little touristy things, (which of course, they ARE
) and so should have a signature of some sort on them.
These "signature marks" were carried out by mostly Eric Dobson, but some were done by Marie - Vicente Boffo's niece, who worked in the packaging department.
It was a marketting thing, but if there is a signature mark on something, it is a superior thing.
The tops can vary considerably too, sometimes a bit think and clunky with tool marks or just a heat finished broken raggedy top. Sometimes they're nice and neat and round.
The biggest difference between the actual construction of these facetted "cubes" that I have noticed is that some contain a "crizzle web" and others do not.