I too have noticed diamond shaped marks on my back. . .when to my dermatologist yesterday, he didn't know what they were either. . .doing a complete blood workup at this point. It doesn't itch or hurt and it's not warm or raised, just feels like the rest of my skin but looks like something "stamped" my back with these diamond shapes. . .I have about 6 of them, 4 are clear and they are in a diamond shaped pattern as well, with a couple marks trailing off the bottom part of the main diamond shape (kind of like a kite with a tail if you will). . .they are evenly spaced and clearly marked. Does anyone have any clue as to what this is, I've had now since Thursday, today is Saturday????