One thing I love is when movies (especially sci-fi movies) mention something that "sounds to good to be true". Unobtanium, dilithium crystals, the list is endless. Things that sound like a joke, but really do exist. One of my favorites is from Star Trek IV, where Engineer Scott and Doctor McCoy trade the formula for "Transparent Aluminum" in order to get Plexiglas. However, are people even aware that there is such a thing? The oldest and most well known is actually the sapphire. This is a natural oxide, with the chemical symbol Al2O3, and based upon other trace minerals in the crystal (iron, cobalt, sulfur, etc) it takes on various shades of color. So this is literally "Transparent Aluminum". But it can go even further. Aluminium oxynitride is a manmade ceramic, and is basically "manmade sapphire". And this has real use, it is used in most of our drones and recon aircraft for it's invisibility to IR sensors. It is currently being researched to make more powerful bulletproof glass, as it's light weight and strength are superior to those currently on the market. A lot of things were predicted in science fiction long before they were real. Touch screens, atomic power and atomic bombs, wearable computers, bionic limbs. But many do not realize that some of the fantastic recent ones are really in existence.