Order a sample and experiment to your heart's content.

I tried the turmeric test on super white and it failed (even though it was sealed). If you do it, try it with turmeric and oil as well as that stains more and most indian dishes will have both fat and turmeric. Also try saffron

I happened to cook with fresh turmeric last weekend on my parents' white quartz (Silestone Bianco Rivers, polished, somewhat similar to Lagoon and Lyra.)

Juice from the freshly cut turmeric stayed on the counter for about 30 minutes and i was able to remove the stain with a wet sponge and soap. I had to rub a bit though, so I would not leave the stain overnight. The counters are 3 years old and free of stains. 'Honed' quartz are said to be more prone to stains though.

Thank you all for your helpful responses:-).
Annkh: I'm having a hard time getting samples in time ...I started late with the countertops :-( and now am maniacally posting online and doing Google searches.
To my delight, the Amazon Pearl quartzite recovered from my overnight turmeric punishment - after I scrubbed with Dove dishwashing liquid and a soft sponge. It is beautiful but I don't see it anywhere online. I asked the salesman and he said he does not know of another name for it but it is very close to Sea Pearl.
GWlolo: Good tip about oil, thanks!
Barthelemy: Thanks a lot - your post eased my mind regarding Silestone. We were set on a polished slab, whatever we choose; I didn't know that honed quartz is more prone to staining..good to know.

Barth - no stains on our Cambria - but it is darker and would be hard to find.

My dad spilled Khoreshte Aloo (Persian Tumeric Plum Chicken Stew) stew all over my Cambria Dovedale counters.

He tried cleaning it himself and not tell me.

A couple of weeks later I found a few drops here and there.

It took a lot of elbow grease but eventually I got it all.

a2gemini and deeageaux: Thanks for the info on Cambria.
Deeageaux, looks like your dad put in a lot of elbow grease too, if you found only a few drops later! :-)