Usage patterns
〈物〉を宝物にするto treasure something; to make something one's prized possession
He treasures that ring as his most prized possession.
一生の宝物a treasure to last a lifetime
This experience became a treasure that will last me a lifetime.
〈人〉にとっての宝物a treasure to someone
Children are a treasure to their parents.
宝物を大切にするto take good care of a treasured possession
I take good care of the treasured possession I got from my grandmother.