Doctor Who: Precious Annihilation (The Tenth Doctor and River Song, #1.2)

When jewels become lethal in the London of 1912, both River and the Doctor turn up to find out why.
A mystery takes them centuries into the past, and onto the high seas, where a superstitious crew edges towards mutiny.
The star-crossed couple are about to find out that, while gemstones inspire jealousy, love can be the deadliest treasure of all...