That is not the fault of your Quartz. That is the fault of your water. You need a whole home water treatment system.

Sorry to say, but the water is the problem. Ever see build up on a large rock in a creek or river? If left alone for a million years it becomes "travertine". It isn't the stone putting it there, it is the water depositing it onto the stone. The stone is inert...the water is depositing calcium onto your counter tops.

A whole system water softener or an under sink softener for this one area = the only option. The only option other than "CLR" every week (and CLR can have issues with some stones so be sure to test on a small patch out of the public eye).

The deposits would have happened if you had concrete, Stainless Steel, wood, etc. The granite is just sitting there minding its own business when the water came along and deposited calcium onto it. Soften the water and you stop the deposits.

We live in a hard water area also. You need to keep the area dry, which means wiping up any water drops as soon as they happen. I have a wash cloth that I keep on the counter just for this. Also wipe down your fixtures so that the minerals don't build up on them over time.

To your question a BRAND NEW single edge razor blade will remove the build up. It's a pain but it's the nature of hard water.

I use CLR, wipe it on heavy and let it stand for a few minutes and then clean it off. All per the directions. I would not use a razor as you run the risk of marring you brand new counter tops. Also check to make sure your new countertops don't need a urethane seal - but the others are correct, your hard water is the culprit not the counter.

Quartz countertops are not manmade or shouldn't be - they are a completely natural product unlike Silestone or the other manmade/fabricated products mentioned. Natural products don't come with a warranty - at least not in my part of the country. My reference was to NATURAL not manmade products. I have REAL QUARTZITE countertops, they don't come with a warranty. Also REAL QUARTZ countertops (Si02) & QUARTZITE are sealed by the fabricators using an industrial silicone based sealer from GranQuarts called 413S but it is not available to individuals. There may be some harder Quartz that can be polished without sealer. The poster should contact the fabricator to determine the best course for his/her specific product. I was told NEVER to take a razor blade to any stone surface because you can mark or scratch the surface or worse, gouge it. Many a glass window has been destroyed via such tactics.

The OP has manmade quartz, (industry standard term) not natural stone quartzite. Even natural stone shouldn't be touched with CLR et al. Sealer digression has diddly to do anything, much less with polishing. Natural stone is polished at the quarry.

Razor blades have been used on glass and stone longer than I've been alive, and that's a loooong time. Sure, you can't make everything idiot proof, as a new model idiot is developed in every generation, but most competent people don't have issues scratching anything with the proper use of a standard razor blade scraper. Especially since the stone is harder than the metal.

Quadruple 0000 extra fine steel wool, with nothing else, and very gently brush the surface where deposits are.

Thanks! OP here - we actually did put in a whole house water softener system and a worker removed the existing stains. But even so sometimes there are deposits - I can’t figure it out. It’s much less but still there. So maybe I will try this when it get built up. Thank you!

Quartz countertops are a ridiculous trend. My management at my complex in AZ ( known for hard water) installed them, I'm assuming to help justify their obscene rent raises. They'gave us no instructions on care. I used Method cleaner, not bleach or anything obviously harsh and my counters are ruined! Quartz is expensive and high maintenance. I can't wait until we see the end of this costly, stupid trend!

Thanks- ya my counters aren’t too bad since we installed the water softener. But not perfect. And, yes, I chose quartz (not quartzite) bc it was supposed to be easy to care for as well as look nice. Not sure it’s so easy and if it gets ruined it won’t look nice, right?