On 24/02/2017 10:12, Martin Brown wrote:
Very hard to tell from a photo.

How it fractures (or not) when bent would distinguish brittle epoxy from
the more flexible silicone or acrylic fillers. It could even be a hot
melt PU glue which would soften when warmed up.

None of the obvious cured polymers will be easily softened by heat apart
from a PU hot melt glue.

I think his best bet is a razor blade or scalpel in parallel to the
bench and done with great care to avoid scratching the granite or
personal injury with sharp thin blades that may shatter if forced.

Some tools sold for dismantling iPads spring to mind as suitable.

Apparently it is `soft/bendy` like silicone so I reckon trying heat to
start with.