I am trying to identify a story from novel that I once read, this was a paperback book. I read this story in the 1990s in a library that had slighter older books so its definitely pre-1990s on the publishing date.
The story is about a rock/jewel/stone (it looks like a diamond, I think) that bestowed healing on anyone who touched it, sustained touch with the stone would heal practically near death-causing injuries, at least one of the characters in the story recovered from cancer, another from a stabbing. As a result, there are parties fighting to get the stone.
It is speculated or implied that the stone is extra-terrestrial hence it would be categorized as a Sci-Fiction book. The novel ends with a lady who finally manages to get the stone/jewel, she then gets it implanted in her so that her body will forever be healing and therefore she will no longer age.
Anyone have any idea of the name of story I am talking about?