Cambria Windermere Experiment
I purchased a 12x12 sample of Cambria Windermere (that's a quartz countertop surface) and put various things on it to see if it would stain.
On the sample, I placed ketchup, a frozen strawberry slice, blueberries and some blueberry syrup, a tangerine wedge, some bleach on a bit of paper towel, and some lemon juice on another bit of paper towel. Then, I drew lines with Sharpie permanent marker in different colors (because in my house, Sharpie accidents happen sometimes). I waited three hours, and then used hot water and a dishcloth on the Cambria. I used absolutely no cleaning product. Everything came off easily right away, except for the Sharpie. I rubbed that area with the dishcloth and noticed that the Sharpie marks were starting to fade, so I kept at it for another full minute. I was making really good progress, but I decided to switch to a Scotch scrubby pad (the green and yellow kind). With only water, the Sharpie marks came out, and the green rough scrubby pad didn't seem to leave any etching or scratch marks on the counter.
Here are the before and after shots (well, rather, the during and after shots). I don't know why they are so huge, because I shrank them down to about 350 pixels square, and they were much smaller at 100% on my computer before I uploaded them to Snapfish. Now they're fuzzy, too! Oh well.