Ok, please please PLEASE don't let this turn into a religious debate or argument here, but this just reminded me of what I thought was a very interesting story. Nail polish has been traditionally not been used by Muslim women. Not the coloring specifically, but because nail polish does not let water through, and that blocks water from coming to contact with the fingernail for a required pre-prayer washing. Removing and re-applying the nail polish is theoretically possible, but for 5 prayers daily it's obviously a hassle. Some Polish guy invented a nail polish that was designed to be breathable, so oxygen would reach the nail. As it turns out, that also allowed water to go through, so this has been a HUGE hit with Muslim women. It wasn't the original intent when the guy invented it, but hey - if you can market a product to a major portion of the population, more power to you!

Breathable nail polish a surprise hit with Muslims | News OK