See that strange rock up there? It’s a nifty trick of geology that’s captured three phases of matter, with a solid exterior, liquid middle, and even a gas bubble to boot, all contained within rock crystal quartz. Liquid-filled rocks form when minerals trap fluids, but depending on their composition they can either be classed as enhydros, enhydro agates, or fluid inclusions. EnhydrosAn enhydro is a hollow nodule that contains water, most often made up of chalcedony – a form of silica that consists of hundreds of thousands of tiny quartz crystals. They develop when groundwater rich in silica flo…