Engineered stone is subject to ultraviolet light degradation, that's why the manufacturers insist fabricators store it inside and why it's never used outside.

Do the yellow stripes line up with any adjacent window treatment?

No, this is in the center of the showroom with no windows near by, I assume they've moved it around so I can't be sure where it has been. And perhaps it can be cleaned off, I don't know. I also don't know if it is from ultraviolet light which is why I'm asking. I just want to make sure it won't be permanent, I'm willing to clean but if anything permanent like yellowing can happen to white quartz then I don't want to choose it.

This is a rather big sample in their showroom, it's not something they lend out so people can do tests on at home. I mean, if I could take it home, I'd see if I can clean that yellow out and if I could I would be way less hesitant on choosing a solid white quartz.

will your bathroom have a large window, left uncovered (and uncoverable?) i'd be wary ordering a white quartz if this was the case.

don't accept a slab that already has yellowing on it.

in my kitchen i have a marble patterned quartz near an old 'plain glass' window. the pattern has patches of cream but i am aware that my mixer could leave a whiter footprint. i keep the blind closed in the afternoon 'in case'.

Are the patches of cream not removable with cleaning?

Yellow is consistent with ultra violet light degradation. Take some acetone and a green ScotchBrite pad to the showroom. If you can't get it off in half a minute, go to plan "B", please.

OMG you really don't have any idea with quartz do you joseph. A green scotchbrite is highly abrasive. So if you do attempt to do this you will destroy the polished finish.

Yellowing can be reversed by a product call Quartz Refresh.

Is there a resource for Quartz Refresh in the US? The only product I can find by this name is from an Australian company with outdated links, at a price of $795.00.

Yes, it turns a bit yellow. I am so sick of it now. Only 2.5 years and only the countertop near sink /2 windows. I wondered & google around. I think is UV issue........

Same, countertop is 3 years old and yellowing. Do disappointing for the money paid!

I saved the cutout from my bathtub and stored it in my garage for ten years. We recently installed it in our guest house as a bath counter and it is horribly yellowed. Any suggestions? The original bathtub surround in the main house is still beautiful.

All this talk about UV. Yes, UV perhaps accelerates yellowing, which I find interesting that so many suppliers store their slabs and remnants outdoors. Nevertheless, even without UV, all resin yellows over time. It’s a chemical fact. I had a small clear glass vase with artificial flowers in it. The vase had clear resin at the bottom, made to look like water. I kept the vase in my powder room for 5 years. The room has always been completely dark because it has no windows. Over that time, the resin became a very yellow-golden, clear color. In the end I had to throw it away because it looked so bad. The same will go for quartz countertops because they all contain resin. The resin gives the countertops their shape and holds the quartz particles together.

It depends upon the sunlight exposure and the color of the engineered stone as to whether or not it will suffer from UV exposure. No estone manufacturer allows exterior storage in direct sunlight, and none of the "exterior' grade estones are dark.

Honestly why do you prefer fake plastic instead of real stone and that includes Corian even if over time it has improved . For crying out loud there are 100s of beautiful reals tones been out in the sun for a very long time never chsnge color.

With or without UV exposure, quartz countertops will yellow, just probably faster with UV. If you google resin yellowing there are many discussions about the fact that all resins yellow. The folks that work with resin are well aware of this fact.

"For crying out loud there are 100s of beautiful reals tones been out in the sun for a very long time never chsnge color."

To make them suitable for use as countertops, many natural stones are resinated at the processing facility. Those stones are subject to UV light damage. Don't make me look up the pictures please.

"...the fact that all resins yellow."

Context please; some more than others.

I purchased a remnant piece of Pental Thassos white quartz (from a local stone shop) for my bathroom / laundry room vanity. Years later, it remains pure white, no stains, no scratces, no chips. I love it! You can’t beat the look of a classic white counter!

Here is some context. https://www.sciencedirect.com/science/article/pii/S0142941822002306

I’m interested in corian but I heard it’s less heat resistant and durable than real or engineered stone, and I can’t figure out if that matters to me or not.

I would never put a burning hot pan down on a countertop on purpose, but there have been times where I put other medium-hot things down (eg pulling a hot microwave dinner out of the microwave before OUCH realizing how hot it was).

I would really like to get quartz for my island and I worry about that also. I love to bake cakes and cookies, and I’ve grown very accustomed to not having to worry about setting a 300 - 500 degree pan from the hot oven down on my current granite island.