This is a question for any hardware expert here. Basically, I've noticed a lightly coloured square on the back of my iPad Air (pic attached), to the left of the apple logo. I'm no expert in metallurgy, so I could be way off, but it seems like the kind of white heat marks you get when you use a blow torch on metal for a long time. Using some photos from ifixit I compared the location of the mark to the location of the components and it seems to be roughly where the A7 chip is located. I'm wondering if it's at all possible that performing intensive tasks on my ipad like playing games could cause the chip to heat up enough to actually leave a mark on the aluminium? I've tried giving it a good clean but it's not a mark that can be removed, and I'm very cautious about resting anything on my ipad. I don't have marks like this anywhere else, so I'm baffled. All theories are welcome.