Which Material Cannot be Used to Make a Lens?

1.  Glass and water are transparent materials. There is a certain amount of plastic that is transparent so that the plastic can be used to make any Lens, but the clay is an opaque substance so that the light cannot be transmitted into it but clay cannot be used to create the Lens. One of the most common ways of creating a Lens is also by using the optical glass but then to make Lens generally crystals and plastics are also utilized and also mirrors are generally constructed out of any which can be polished or reflected.