Hand made sterling silver chains crafted by the EM Teller family of Navajo artists.  They are signed.   You will not believe how nice these are.  They come in 18 inches or 20 inches with a two inch extension.  Even the clasp and extension is stamped.  A picture next to a mechanical pencil was included so you could see the width.  18 inch chains are $600 and 20 inch chains are $720.
 
I have the family's permission to credit their work by name.