Tuff Rhino sells Mira Cool items with the water retaining crystals.
I had one of these do-rags with a 1" row of crystals across the forehead until I wore it out. Rag is simple cotton. Once full of water, the forehead band will not fit under a well fitting helmet, so I would slip it forward just below the crown of my Scorpion EXO100. I'm not sure it would work with a full face.
Used in hot weather, I would add one of their cooling crystal bandanas around my neck. They would hold water all day, and evaporation at headband
and neck was pretty nice...... thou eventually the water is just as hot as your head... thou still wet. I charge several with water, then place them in a ziplock in the fridge, then throw them in the bags in the morning, and still cool later in the day when needed.
http://www.tuffrhino.com/Skull_Cap_p/hs3014.htmhttp://www.tuffrhino.com/Cooling_Apparel_and_Products_s/43.htm