historical fiction with jewel sewn into man's head for smuggling or just plain concealment

[Pieter]

The book is historical fiction, perhaps set in Venice (or some other real-world location).

It follows a boy/man who leaves home and goes on an adventure - I think he leaves his mother behind (who's maybe in debt). He procures a large diamond along the way. This diamond gets sewn into his scalp at some point so that it won't be found when they go through a particular region. He gets some visions/dreams after the diamond implant (almost like superpowers).

I think he was travelling with 2 companions, male and female, and feel he travelled through desert-type terrain. I read it sometime around 2010, give or take a couple of years.

[Kris]

Pieter, what is the story's time period? Would you say he definitely starts in Europe?

[Pieter]

Would place it before the 1800s but difficult to pin down more than that. Not 100% sure of European setting - it might've been North Africa or the Mediterranean.