[Brightcolours]

No (lead?) crystal was used for lens elements, but rather lead glass (glass lacks a crystalline structure). The only crystal I know of that gets used in lenses is fluorite. Of course, lenses that have lead glass elements usually also have other types of glass in other elements, it depends on the refractive properties wanted for the element.
The use of lead glass (glass containing lead oxide) for its refractive properties was pretty common anyway, but because the production od lead oxide glass is a source of pollution, lead oxides in optical glass has been replaced with other metal oxides.