I know that High-energy (hard) X-ray light cannot be focused as easily as visible light by using a burning glass. But why is this? If there was x ray light spread over a normal sized lens with the same intensity as sun light why couldn't it focus? would the material needed for say 50cm^2 magnifying glass light focuser object need to be special? could very intense radio waves in the same manner be focused over the same area or any other em waves? whats special about sunlight?