I found one website that calls it a marble-look quartzite. Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. So, it isn't marble although it resembles it. Granite, instead of being metamorphic (stone that is created thru heat and pressure from another material like sand) is an igneous rock (of volcanic origin - meaning lava that has cooled and hardened).

A lot of marbles are being sold as other stones because of marketing, not geology. It's marble if it etches. I'd bet on an etch. Test it with a lemon.

Because they have learned that calling it marble scares people away from using it. And rightly so. Marble will etch. True granite or quartzite will not. Get out your lemon and see if it etches your sample.

Marble patina · More Info

Super White is a quartzite but it does etch. It is harder than marble and that's why a lot of people call it granite, though it is not as durable as granite.

It's a great stone to use, but like any stone you should educate yourself of how to care for it properly. I would have your fabricator hone the stone, that way when it etches you won't notice :)