I am a fabricator. Unfortunately I suspect this is a case where the slab supplier sent the fabricator "butterfly" or "mirrored" slabs that don't have a perfect color match. If the parts were not seamed together you'd never notice but seams are the reason people buy "mirrored" slabs. If there is a way to appreciably darken or lighten quartz I'm not aware of it. The non-porous nature of engineered stone makes it impossible to use many of the techniques that work on porous material. At this point the fabricator could replace the small piece with a remnant from the slab used to make the large piece (assuming he has one) but you would lose the excellent grain transition across the seam you have now. Alternatively, the fabricator could ask the supplier to provide another pair of mirrored slabs that actually match in color at the slab suppliers cost and then remake both pieces. Several years ago I stopped buying slabs from a major quartz brand because I couldn't assume all the slabs of a given color would actually match. Ask your fabricator what he suggests. If he's a quality shop he should be willing to work with you.

Do any of you think it matters that he hasn't finished yet? I'm trying to be hopeful here, because if I have to go another route it's going to be a few weeks wait from other companies and I'm going to have to handle the situation of not paying him. I know he not going to folk up the $ for me to repurchase, so I'm going to have to just withhold payment.

Only that that area will chip easier and easier as the chip gets larger and it gets contaminated from crap you cannot clean out.

Rita, I'm blushing!!!! I love my kitchen, too! Rita and I are the resident "fanboys" for Glacier White Corian. It really is pretty much bullet-proof, and it LASTS!!! My kitchen counters were first installed in early 1985!!! I re-used them (and added a 5' ft new counter) 3 years ago. One cannot do this with just about any other material. It's a great value and a very high quality product. Don't allow any Big Box store employee or other idiot to tell you it's "low-end". It's NOT! In fact, it is used extensively in multi-million dollar, architect-designed custom houses in the UK and Europe.