Chances are, if you’re a physicist, you pronounce it to rhyme with “park.” And if you’re a graphic designer, you pronounce it to rhyme with “pork.”
I pronounce it both ways, depending on context. And by the way, is there any other word that ends with “ark” that ***ever ***rhymes with “pork”?
But it *is *quark-like-park, because of “Three quarks for Muster Mark”. Simple! Where’s the confusion?
Silly graphics designers…
Quarks are for kids?
Seriously? I mean, don’t get me wrong – pork has many, many fine uses, both industrially and around the house. But rhyming with “quark” simply isn’t one of them.
“Throatwarbler Mangrove.”
I don’t know why, but I’ve always pronounced it (at least mentally) to rhyme with “pork.” I first encountered it in studying physics, but in recent years I’ve encountered it far more often in relation to graphic design.
If you’d first encountered it reading Ulysses, you’d have rhymed it with Mark.
Physics: to rhyme with park.
Graphic design in Ireland: to rhyme with pork.
Graphic design in UK: to rhyme with park.
Yoghurt-type product: to rhyme with pork.
It’s very confusing.
You have that in English? Interesting. I remember English speakers who didn’t know a good translation for German “Quark” (rhymes with “park”) but perhaps they were Americans.
I have watched “Trading Spouses” exactly twice, and both times it was the same episode, with a kind of laid-back, New Age mother trading places with fundamentalist Christian virago. Towards the end of the show, she launches into a complete foam-flecked tirade about the other family, condemning them all for being from the “dork side.” It took me a couple of minutes to figure out she was saying “dark side.” I don’t know if that’s regional pronunciation or not. I can’t remember where she was from.
Or Finnegans Wake, even.
If you’re buying it in continental Europe and sticking it on your muesli it’s “Kvark.”
I’ve always rhymed it with “park.” Astrophysicist Jim Webb knows better than to quive on a quarkway, though. 
I suspect people tend to rhyme “quark” with “pork” because of familiarity with other words beginning with “quar-” such as “quart,” “quarry,” “quarter,” “quarrel,” in which the “a” tends to be pronounced as in “war.”
I thought it rhymed with park. Never heard anyone use the “pork” version.
Old joke:
What is a quark?
The noise made by a VERY well bred duck.
I rhyme it with ‘park’ and I’m a Graphic Designer*
*a British one though, if that make’s a difference.