Autonite (Hydrated Calcium Uranyl Phosphate) is a yellow – greenish fluorescent mineral with a Hardness of 2 – 2Â½. Due to the high content in uranium, it is radioactive and also used as uranium ore. If the mineral dries out, it converts to meta-autunite-I, which can turn into meta-autunite-II after heating. These two subsequent minerals are very rare in nature. For scientific studies it is recommended to store the mineral in a sealed container to minimize the water loss. Museums are known to have covered the mineral with lacquer to avoid drying of the mineral.