Supplier or ideas for stone shower bench?

[Concrete guy]

Quartz really doesn't cope with temperature change all that well. Some makes struggle with moisture, others fade in UV light and many are susceptible to etching when exposed to chemical.

Whilst natural stone (particularly marble) will also etch/discolour. It's a lot easier to refinish, particularly surface refinishing.

I'm not a fan of quartz mainly due to the difficulties in maintenance and refinishing long term.