I’m looking for a children’s book that was available around 1990 (not sure if that is the publication date or not). The story details I can remember are that a girl is either kidnapped or befriended by a fairy, and her mother tries to get her back. When the mother finds the daughter, she is told she has to hold on to her no matter what. The fairy then turns the daughter into different things trying to get the mother to let go (snakes, thorns, and finally hot iron). As the mom holds on to the hot-iron version of the daughter, the metal melts and turns back into the actual girl and they can leave together.
The version of this book that I remember had gorgeous illustrations in sort of an art-nouveau/greek style. Very detailed and beautiful. Thank you for the help in identifying the title/author!
Sounds like a Tam Lin retelling. I found this page: http://www.tam-lin.org/library/fiction.html
and out of all the titles, THE MAGIC WELL by Maida Silverman and illustrated by Manuel Boix sounds like a possibility.
This blog has photos of the inside of the book: http://bos33.blogspot.com/2015/07/silverman-maida-magic-well.html
You are a miracle worker! This is exactly it! Thank you so much!
Also, The Perilous Gard by Elizabeth Marie Pope
Another along those lines: The Perilous Gard by Elizabeth Marie Pope