On 9 Mar, 14:49, Gus wrote:
I recently acquired several pieces of chem lab benchtop material from
a Freecycle board, with the idea of using them for -- something.

Solid black resin sounds like "Trespa", or your contry's local
equivalent. It's a fabric reinforced / resin composite. Machines
beautifully, but it's more like metalworking than woodworking.
Micarta is very similar stuff. Small offcuts of this are good for
making knife handles and the like. Repeated dishwashing fades tham and
the fabric starts to show through, in a way that's not unpleasant.