The Tears of the Salamander by Peter Dickinson
Mount Etna towers above the remote villa where Alfredo lives with his uncle after a fire wipes out his family. At first he believes mysterious Uncle Giorgio has saved his life, but the man they call the Master of the Mountain is an evil sorcerer with a terrible fate planned for the boy. Deep within the molten veins of Etna swim the magical salamanders, whose tears can cure all mortal ills. Alfredo must use his own strange powers to protect them, destroy his uncle, and control the explosive rage of the volcano . . .
'If you took a poll now to find out who people think is thee greatest living children's author; the result would be tediously predictable. Potter trumps all. But what would happen if you brought criteria other than immediate popularity into the picture - awarding points for originality, intelligence, clarity of style, emotional depth, and sheer range? There is not much doubt, in my mind, that the winner would be Peter Dickinson' Robert Hanks The Independent Magazine