Elfin – having to do with elves : looking like an elf
http://www.merriam-webster.com/dictionary/elfin
Found in ” The Shawl by Cynthia Ozlick
One mite of a tooth tip sticking up in the bottom gum, how shining, an elfin tombstone of white marble gleaming there.
I think the narrator was describing how tiny Magda’s tooth looked in her mouth.