Back in 2009, my office had a kitchen installed with a countertop I could have sworn was some sort of polished sedimentary stone that just looked too good. I was concerned at the time that the coffee maker (with is always surrounded by drips) would damage it (marble would surely have been etched by that). Well, it's Quartz, and it still looks like the day it was installed.
In 2018, I had a white Quartz countertop put into my basement kitchen. The occupant is a coffee slob, and there was significant staining around his coffee maker. In 2020, I had a sewage flood that required me to gut the kitchen. The remediator carefully removed the Quartz, and I eventually had the same installer come back to put it back in when the repairs were done. He asked me if I had any unsanded grout (I did not). We eventually settled on Bar Keeper's Friend mixed with acetone (that I had), and just a few seconds of rubbing and the staining was GONE. I cannot imagine what could actually stain Quartz (beneath the surface where you can't just rub it off). Purple PVC primer?
Anyway, unsanded grout is apparently abrasive enough to remove anything from Quartz, without actually dulling the polished surface. Pumice is probably the best bet.
Yeah, the prices online seem to be great, but there's absolutely no way I'd try to install a stone countertop over maybe 60" on my own. Its just too heavy and risky. I did the granite in my kitchen, and man was that island top heavy, but my galley design and farmhouse sink broke up everything into manageable pieces. Your big section is way past what I'd try.
These are the guys who did my basement Quartz. Might want to give them a shout, but I can't say they're going to be far different from the going rate.
Wilstone Incorporation is a custom natural stone fabrication and installation business. We are a privately owned business with more than 17 years of experience
wilstoneinc.com