Try dripping a few droplets of water in the same area. If the water beads up (i.e., doesn't absorb into the stone and leave dark/shadowy spots), it's likely the ring is an oil stain -- which means your contractor likely didn't use a sealer that protects against both water- and oil-based liquids. Any idea what brand he used? Also, what type quartzite do you have? Close-up looks similar to my Calacatta Gold.

Sorry for late response to both of you. I don't have any other pictures at the moment, sorry. @AmyK we used a hair dryer to get one ring mostly off and one about half gone. Haven't tried ever since; the pandemic and everything has side-tracked us. We haven't been able to reseal it either, although because we know what stains it, we've figured out how to mostly avoid more issues. We typically just put down a towel in the most-used area and just ensure we wipe everything up (water, juice, etc.) before it penetrates the stone.

Patricia - From my research, quartzite is already rather water-resistant but (as is all natural stone) is still porous. So the recommended sealant, I think, is just recommended to help deter water seeping in. I think we can spray the sealant from a canister and (for us) would not be too much upkeep. Live_wire_oak - the house has a drainage plane (typar, foam, the works) and the stucco guys have added the extra wire backing for the areas we intend to put stone (whether it be the quartzite or other typical exterior house stone). Is there something different with quartzite we have to consider?

We do not have edge staining. The only place we notice any change in color is along the seam where our faucet is. And mostly when my MIL decides to wash dishes at the holidays. LOL. Our dish towels are nearby and I just wipe up any excess water. If water does get through the seam and discolors the stone, it dries within a day and it’s back to normal. No issues like what is reported here. Our quartzite was labeled as Mykonos... looks to be similar to a Macaubus. We’ve had it almost a year and a half. We seal it twice a year. Takes about an hour to do (more so with dry time between sealant applications), but I can easily multitask and do other things, honestly it is not a big deal at all.