Silverpoint is a soft silver line, much like pencil but not erasable. Popular in the early Renaissance artists such as Jan van Eyck, da Vinci, Durer and Raphael used the medium to create very delicate, detailed works.
It goes on a soft silver color with a medium range of light to dark. After a short period of time exposed to the air it will tarnish to a warm grey. I love that aspect of this medium, that it continues to change after the artist is done with it.