The mat is not transparent. It is black and made of silicone with reinforced fabric.

Doesn't say on the packaging.

It can be cleaned wonderfully with a little washing-up liquid and a sponge. I don't know if it is dishwasher safe.

I would say yes, as long as it is well floured and you don't scrape the cutter back and forth too hard.... I once cut a pastry with a butter knife and there were a few scratches/light cuts....