Small charm from Lumos representing the golden egg.

At least 15% of the sale price of this piece of jewelry goes to the Lumos Foundation, a nonprofit organization founded by J.K. Rowling that advocates for disadvantaged children in care.

A charm bracelet may seem like a small, worthless item. But what other piece of jewelry is so deeply connected with memories and emotions? Why are these little masterpieces called "charms" if not to allude to their talismanic qualities? They hold a significance that goes beyond that of a simple piece of jewelry. They are true personal amulets.

Lumos is a spell I created in Harry Potter to bring light to a hopelessly dark and frightening place. At Lumos, we do exactly that: we bring to the forefront the left behind, forgotten, and hidden children so that everyone understands their situation and works hand in hand to help them out.

• J.K. Rowling, Founder and Chair of Lumos.