> These are gun-like devices that you point to a material, it shines x-ray on it and analyze the rays that comes back, which allows it to determine the elementa

> These are gun-like devices that you point to a material, it shines x-ray on it and analyze the rays that comes back, which allows it to determine the elemental composition and percentages of the material for free in a few seconds. Like magic. Hasn't that been around, in handheld form since the 60s? I think they're called tricorders.