On 19/08/2019 10:30, The Natural Philosopher wrote:

I no longer care what they are. They withstand almost anything and are
bomb proof and I like em

Never been sealed :-)

Like I said, Granite (or gabbro, or basalt!) I can believe.

Quartz?

https://www.surreymarbleandgranite.co.uk/what-are-quartz-worktops-made-of/

"Quartz worktops are made of pieces of natural stone bonded together
with a small amount of adhesive."

Andy