I am not an expert on Quartize, but that doesn't look right to me. The edge on my marble is mitered, so it is hardly visable. I do have a round piece at my island, that couldn't be mitered, but it is nowhere near as visible as yours. And that vertical seam on the ourter edge is odd.

I am a fabricator. For a laminated edge it's typical on a near white stone. The vertical seam is because the fabricator didn't have enough material to make all the laminated pieces without it. You would have been much better off with a mitered edge done properly. However, it's more difficult to do, particularly on quartzite, unless you have the right equipment.

When I remodeled my kitchen in CA my quartzite was 2 cm so I also did a plain built up edge. My fabricator did a much better job at matching up the pattern, doing a tight seam and a better color match for the adhesive, but it is still noticeable as a built up edge. I used Taj Mahal quartzite, which has more movement/pattern, which I think is easier to match than the very distinct lines/veins in your quartzite.

Thank you! @granitecityservices, is there anything we can do at this point to make the line less noticeable? It’s our first remodel, so we didn’t know to ask for a sample (or buy a thicker stone). The fabricator also cut our island incorrectly (wrong dimensions) and had enough left over to cut an entirely new island (being done tomorrow). So, it doesn’t make sense to me that he made vertical cuts like that with so much excess stone.

In this case, he’s really messed up 3 slabs and now has used all the excess so we can’t do much with what’s left.

Should we demand new stone and new fabrication (the stone is from a different place)?

"is there anything we can do at this point to make the line less noticeable?"

No. Your fabricator failed to color match his adhesive. I'm betting he used clear which always shows up as the medium gray you have. With the poor quality and thickness of the seam line, it appears he pulled the mesh off the back and laminated without any prep work whatsoever.

"Should we demand new stone and new fabrication (the stone is from a different place)?"

I would. You're actually doing him a favor by making him eat this. He will get away with such poor work as long as he can. A customer has to make him stop sooner or later.

Our marble has a mitered edge. It looks beautiful. If you re-do your island, get the mitered edge. Pricey, but worth it.