What type of material is this shower base?
It looks like terrazzo, but it's really hard to tell the details. Stone chips are easy to identify, the material between them is tricky. It can be:

some kind of resin / polymer
concrete

Terrazzo is known to be made with both of these, and it is not possible to tell them apart just by looking on photos. So you probably need to ask for cleaning fluid safe for both.
It's tempting to assume resin because it's shower, but I did see concrete-based terrazzo in bathrooms, too.