This strange crystal acts like metal and glass at the same time

A remarkable crystal called molybdenum oxychloride could help make futuristic technologies like smart contact lenses and ultrathin AR glasses a reality. Scientists have created the first detailed experimental map of its optical properties, revealing the strongest light-bending effect ever measured in a natural material. The crystal can act either like a reflective metal or transparent glass, allowing it to manipulate light with extraordinary efficiency while being thousands of times thinner than a human hair.